Project SS UU Research Week - UU RESEARCH - Week 42 Roost Hydreigon and Any sets Crobat - New System !

[Rawbi]

Okay a bit early but as two of the teams I used had Prim or Gyara on it and I don't feel like making more for just another day, my thoughts:

Tried two Tox sets this week. The second set was standard Specs. Not a whole lot to say about it. Hits very hard, but locking yourself into Normal, Poison, or Electric moves invites free switch-ins.

The first set comes from the Next Best Thing thread in the OU forum: AV Tox. Tox's typing gives it resistances to three prominent (special) offensive types: Electric, Grass, and Fairy as well as the less common Bug, Poison, and Flying. That base 70 SpDef isn't doing any favors though. Giving it an AV brings you up to a decent 265 SpDef, which means you can use Tox as a check to things like Roserade, G-Weezing, and even Gardevoir in a pinch. Another nice thing is AV bluffs a Choice item, so you can potentially nuke something like a Mamoswine on the switch with Boomburst predicting another move. The downside is this lacks in power compared to Specs or Expert Belt, so it's questionably viable, but hey.

squad

Other gimmicks I considered included Nuzzle and mixed Drain Punch. Tox's counters would be better off Burned or Toxic'd instead of Paralyzed so it's likely a very niche option. And Drain Punch does bupkis even with +1 so lmao don't even bother.

I never got around to Necrozma

 

[Daiyaga]

Lilburr Elias PSY A Cake Wearing A Hat ThatOneRandomBoi Reminder to post your write-ups before the deadline hits.

 

[Elias PSY]

SD Necrozma

Necrozma @ Lum Berry
Ability: Prism Armor
EVs: 4 HP / 252 Atk / 252 Spe
Jolly Nature
- Swords Dance
- Photon Geyser
- Earthquake
- Knock Off

Played 36 games with sd set,dragon dance is cool too but outside of offensives teams(mainly with screens) he is underwhelming because he lack firepower and speed imo.
Necrozma has good match-up against bulkiers builds thanks to knock off(cripple his counters),set-up swords dance on passives mon like milotic and weezing and prism armor who makes it surprisingly bulky (eat a band first impresssion from sirfetch'd,non specs chandelure's shadow ball).
Necrozma hates chip damages(including status)so lum berry is great in him.
Overall it's good pick on the current meta but he need some supports to beat his counters and hazard control

team i used (max speed doublade is a good partner because he can outspeed umbreon and kill it with +2 close combat)

 

[A Cake Wearing A Hat]

So, I also used Swords Dance Necrozma with Lum Berry, this time ft. X-Scissor for Umbreon and Celebi. This set was alright? It's not a super great wallbreaker but it's definitely good at breaking past, like, bulky waters. It's disappointing that it can't break past a healthy Umbreon or Doublade, but it definitely put in enough work for me to consider the set viable. Lum SD is probably croz's best physical setup set.

I used pretty much only Specs Toxtricity throughout my laddering. It was an extremely powerful wallbreaker, but it again can't really break past a healthy Umbreon, and using it is a constant series of mind games as to what you need to click to not get punished heavily. Its STABs are strong, but also very easily punishable due to immunities.

I remember not OHKOing a Sirfetch'd with Boomburst once. I think it was max HP. It was still disappointing.

Be that as it may, though, Specs Toxtricity is a really solid wallbreaker and something I'd definitely consider using in the future.

 

[Lily]

Just a quick writeup because I really didn't remember to do this and by the time I did, I was lacking time. Sorry! :<



I used a bunch of Specs Toxtricity and I have to say that it's super good. It struggles with Rhyperior and Gigalith, sure, but I ran one with Toxic in the last slot to make that much more of a non-issue. I think it's a super solid breaker and has many more options that are unexplored; I had a little bit of fun with Venoshock + Hex with tspikes support but didn't do enough with it to consider it seriously viable. I ran into a few Togedemarus and they walled me. I don't know who you are, but I love you.



I tried this thing out, not on my RW alt but I figured I'd give some thoughts on it. It's incredibly versatile, super strong and pretty bulky too. I like DD sets, offensive rocks sets, and WP sets under screens (I spammed this a lot). It's absurdly fun to use and an absolute menace to face too. Hopefully it gets a lot more exploration in future!

Sorry that this isn't that long, I'll hopefully have a bit more to say next week :c

 

[DraconicLepus]

Alright, that's another week over and our winner for this week is Elias PSY. Congratulations!

The punk rock mon Toxtricity got great feedback! The most common set used was Choice Specs, along with some interesting choices such as Life Orb used by Notily and Assault Vest used by Rawbi. It has a very unique typing in Electric/Poison lets it absorb toxic spikes and switch into pokemon such as Galarian Weezing and Roserade, told by Rawbi and Notily. Though due to its poor bulk it can easily get chipped and put it in range of pokemon it could check. In terms of specs, both A Cake Wearing A Hat and Lilburr agree that it is a terrific wallbreaker. It struggles against common walls such as Rhyperior, Gigalith, and Umbreon. It needs to be played well due to both of its stabs being immune, but its high power moves make it a forced to be reckoned with.

Necrozma had a bit less success, but was found to be a good pokemon with physical setup in the right situations. Swords Dance was the most tested set, used by Elias PSY A Cake Wearing A Hat and Dragon Dance was used by Lilburr. Against offensive teams it was lacking due to its low speed and starting firepower noted by Elias PSY but was great against fatter teams due to being able to much more easily get up its boosts. A Cake Wearing A Hat says its not able to break through a healthy umbreon, but due to the coverage it gets its able to deal with more defensive teams very well. Overall a decent wallbreaker in the tier

Onto next weeks picks!

Set

Araquanid @ any item
Ability: Water Bubble
EVs: any
- Substitute
-Toxic
-
-

Set

Runerigus @ any item
Ability: Wandering Spirit
EVs: any
-
-
-
-

Araquanid has always been known as a slow, but strong sticky web setter. But this week we aren't exploring its already known webs set, but another one. With its typing in Water/Bug its able to provide a lot of defensive utility. Substitute+Toxic has been a set brought up, but still quite underexplored. With Noivern being as common as it is will this set shine, or will its niche stay the same as its always been?

Runerigus is an interesting choice. It's the Galarian form of Cofagrigus and with its Ground/Ghost typing it provides itself as one of the best toxtricity checks along with a multitude of other pokemon such as Cobalion and Gigalith. With multiple hazard options such as toxic spikes and rocks, its able to fill a role most pokemon cannot. Will its unique typing and defensive prowess allow it to shine in the current UU meta when it otherwise went unseen?

In order to participate you must do the following:

• Post here with a fresh RW alt (such as SSRW5 Daiyaga or SSRW5 Cake) and the name(s) of the Pokemon you will be using.
• Use at least one of the Pokemon being researched.
• Post your experiences with the Pokemon you're using, participate in the discussion!
• Post logs of this Pokemon in action against other teams - don't just tell us, show us
• The winner of the challenge will be the person who has the highest ladder ranking on the Pokemon Showdown UU ladder with their RW alt at the time the challenge ends. Winners will also receive a permanent spot in this thread's Hall of Fame.

This week will end on Sunday, March 22nd at 11:59 GMT -6

 

[Eve]

This looks like a good excuse to ladder :) registering as SSRW5 Eve

 

[A Cake Wearing A Hat]

SSRW5 e

in to test things

 

[Fupita Nyong'o]

SSRW5 Fup

Will test Runey

 

[ramolost]

SSRW5 Ramolost
testing rune

 

[platinumCheesecake]

So I'm just screwing around with tspikes rune + cm acid armor clus atm, and while it's a decent solution to a lot of physical mons, it is absolutely deadweight in any matchup involving a weezing. Weezing laughs at everything rune tries to do and defogs away whatever hazards you try to set up. Furthermore, I've found that in matchups without a weezing, rune exists to set up hazards and die. Once I get my tspikes up, I find that I rarely care what happens to the mon, and often hope it gets revenge killed so I don't have to worry about scary threats setting up on it. Substitute anything is a problem, as rune's mediocre uninvested attack means it can often struggle to punch past sturdier subs. And worse yet, both of the tier's wishpassers in vaporeon and umbreon laugh at just about anything rune does and can use it for free heal bells and wishes while rune struggles to get anything done.

I feel this mon would be better on a trick room team where it can utilize its array of hazards and memento itself to keep up momentum, instead of turning into a midgame momentum sinkhole that makes you scared every turn its out that you're coming out worse for it.

 

[HiddenPower23]

I also tried Rune with Toxic Spikes and Calm Mind Reuniclus(no Acid Armour). Just like platinumCheesecake above this post, I found Rune too passive to have a meaningful effect on the battle. In my mind both Drapion and Roserade offer more as Toxic Spikes users.

 

[ramolost]

ok so i did some games w rune :

heres the set is used

Set

Runerigus @ Leftovers
Ability: Wandering Spirit
Shiny: Yes
EVs: 252 HP / 4 Atk / 252 Def
Impish Nature
- Toxic Spikes
- Night Shade
- Earthquake
- Protect

i did 2 teams : one fat balance w bu braviary which was pretty bad did like 15 games w it it only worked coz low ladd (team here https://pokepast.es/5ec69c8d9cb79ab2) and then i built another balance around rune and fat venu knock off to remove the boots which was a way better team and funnier to use (team here : https://pokepast.es/c704023de271e20e)

What i found abt rune is that, beside walling tox, this mon is horrible : u can barely set tspikes coz every defoggers defogs on it. it really suffers from not having toxic. it can stop some dumb hos with luke / tox but beside that if theres mons with recover / toxic / defog rune does jack shit. U usually prefer rockers like rhyp or giga who also lowkey wall tox or every other tspikes. So : dont use that set. Ig a tr set memento could work too but TR is hella gimmicky so fuck that
in conclusion : DONT USE THAT MON ITS JUST A GOLURK OF THE POOR

edit : if u want to use the second team i would highly recommand to go for incin over rune since rune is horseshit

 

[Fupita Nyong'o]

I tested out all the Runerigus sets I could think of. Its low base HP makes it a bad option as a wall. It doesn't have any moves to build momentum (except for one, glaring exception, which I'll get into later), and no reliable recovery. For these reasons, it doesn't have much utility in a stall team, it doesn't work as a pivot, and it doesn't really work as a defensive wall. His lack of recovery means he's very easy to wear down over the course of the game. Weezing is his absolute nightmare, with its immunity to Earthquake and Runey's inability to deal with being poisoned.

But maybe I'm being too harsh. Let's talk about its positives. It has a monster defense stat and a serviceable Sp.Def stat. Its ghost typing makes it one of the few defensive spin blockers in the tier. Spin blocking with Chandelure is risky because of a) its weakness to rocks gives you limited switch ins and b) your predictions have to be perfect every time you bring Chandy in. Runey is much easier to switch in - it can take most non-supereffective moves on the chin.

And let's talk about his ability, Wandering Spirit. Wandering Spirit is great in 1% of situations. The rest of the time it's a non-factor. This ability makes him the perfect Machamp stopper. Flame Orb Guts Machamp? You're now a burned Wandering Spirit Machamp. No Guard Dynamicpunch Machamp? Have fun with hitting D-Punches with Wandering Spirit. If you pair Runerigus with Weezing-Galar, he could make a good stop to a sweep-threatening Haxorus. Switch in Runey, give Hax Wandering Spirit, and now you have an invincible Weezing, so long as Hax doesn't have Iron Tail.

This is a good snapshot of the kind of mon Runey is. He needs a lot of help to be useful, which is the biggest takeaway from this whole exercise.

Runey's best attribute though, is unquestionably his moveset. Will-O to neutralize physical attackers. Access to Stealth Rock and T-Spikes. He's got Trick (I've used a Trick set, with Lagging Tail. Verdict: Meh), and Trick Room. The only problem is that his pathetic speed makes him pretty much dead weight if you're trying to use him for momentum or defense. Even something like Pain Split would help here. So, for my money, Runey's best move is actually Memento. Yup. The best way to use Runey is just to kill him off.

I am proud to present FUPA Fan's certified best Runerigus set: Kamikaze.

Set

Kamikaze (Runerigus) @ Colbur Berry
Ability: Wandering Spirit
EVs: 252 HP / 196 Def / 60 SpD
Impish Nature
IVs: 0 Atk
- Memento
- Will-O-Wisp
- Night Shade
- Toxic Spikes/Stealth Rock

Here's the logic behind this set. Runey absolutely laughs at the very sight of Toxtricity with its unreal anti-Tox typing, so I didn't need any more than 60 EVs in Sp.Def. Runey's ground typing makes him susceptible to Grass and Water, which are very common Sp.Atk types. So I figured I'd be switching into a physical attacker most of the time. Hence the EV spread. Memento is the star of the show with this set. Runey's entire purpose is to wear down opposing mons to the point where Memento can bring in a sweeper to finish off the game. Runey is simply not a plug and play sort of mon. He needs the perfect team around him. Because we're using Runey as a set-up guy to the sweeper closer, we're gonna need a) residual damage on the rest of the opposing team to easily one-shot, and b) hazards to break Sturdy and Focus Sash.

Here was Runey's best game. I recommend watching the whole thing, because I pivot around Runerigus a lot, and my opponent is constantly being pressured by Runey's versatility. But the highlight moments are Turn 4, when he comes in for the first time and pressures pivot Incineroar immediately. Turn 11, when he spin blocks for the first time, and starts slowly chipping away with Night Shade. And finally Turn 35, Runey's last stand. After having chipped away at the opponent, he's ready to give his own life for the team. He Mementos, giving Haxorus a free DD. That +1 speed is all it takes to finish what Runey's started.

Do I recommend building around Suicide Runerigus? No. But if you absolutely are set on doing so, this is how I would do it.

Bonus:
The team. Gameplan is: get hazards up -> wear down with residual damage and constant pivoting -> Runey suicide -> Profit?

 

[Scarfire]

SSRW5 Acey!

Testing both =]

 

[A Cake Wearing A Hat]

I will update my post as I research.

Immediately Araquanid is hilarious, this was my first game. https://replay.pokemonshowdown.com/gen8uu-1082563611.

Araquanid @ Leftovers
Ability: Water Bubble
EVs: 252 Atk / 4 SpD / 252 Spe
Adamant Nature
- Substitute
- Toxic
- Liquidation
- Protect

SubTox Araquanid is easily one of my favorite things I've tested this generation. It just kind of dances on any form of fat, and with Protect, it also dances really hard on any choice item user. I have countless times scouted a Choice-locked electric-type (which, on ladder, most are) and just Substituted again on the Volt Switch. It's also really fun to just take out Blastoise that try to set up on it, since ladder's been spamming the absolute fuck out of that mon. I've found a viable strategy is to pretend Araquanid is a Sticky Web lead turn 1, only to set Substitute when they attempt to exchange hazards or set up on the webs turn. It immediately puts the opponent at a massive disadvantage and it's just great. As a note, though, this set really likes Heal Bell support, since it's going to occasioanlly be taking Toxics from fat waters on the switch so it can Toxic them in return. Also, running Protect means this set won't be able to check Celebi, which can be problematic depending on the team. Protect's REALLY good otherwise, though.

https://replay.pokemonshowdown.com/gen8uu-1082571286
https://replay.pokemonshowdown.com/gen8uu-1082593550
https://replay.pokemonshowdown.com/gen8uu-1082568511
Some bonus replays of Araquanid messing some shit up.

Runerigus @ Leftovers
Ability: Wandering Spirit
EVs: 252 HP / 252 Def / 4 Spe
Impish Nature
- Stealth Rock
- Body Press
- Earthquake
- Will-O-Wisp

Runerigus is, as most have said above, not that great when there's not a Toxtricity. It's passive, and there's a bit too many things it lets in. I only used it over Togedemaru on this team because it's Research Week, but I still feel Togedemaru would do better in the "bulky Tox answer" role. It works enough, though. It's very fat, enough so that it can take a hit from Mamoswine in a pinch. As a note: Runerigus almost requires being paired with Umbreon. Umbreon does so much for Rune - answers the special attackers like Noivern it often lets in, passes it Wishes, provides Heal Bell support, and more. In return, Runerigus handles the Fighting-types Umbreon struggles heavily with in Machamp and Cobalion. I would go as far as to say that if Runerigus isn't paired with Umbreon, you aren't using Runerigus to its fullest potential.

Oh, but don't get me wrong. When there's a Toxtricity, Runerigus stops it HARD. Turns it into a complete liability. It's very good in these matchups. https://replay.pokemonshowdown.com/gen8uu-1083485126

Rune can still handle Heliolisk in a pinch with its bulk, by the way. It's not frail specially, by any means. Also ft. stalling out sun turns with Araquanid. https://replay.pokemonshowdown.com/gen8uu-1083511879

 

[Eve]

This research task found me my new absolute favourite Pokemon to use in UU. God this mon is good, and Sub Toxic is the al de la cremie. Being able to turn the tables on the few bulky Pokemon that can handle its attacks is absolutely phenomenal. Its issues with Noivern forcing it out are as present as ever with this set, but the fact that you can catch it on switchin with a Toxic means SubTox fares a little better than other variants. Leech Life actually feels really useful on this set compared to how weak it feels on others, compensating for Substitute's repeated HP drain very nicely. I bodied so many people with this thing. Really, use it. My team probably isn't optimal but here it is if you want it- it comes with an explanation of the chosen set's EVs.
Replays (I think I forgot to save a few good ones)
It kinda just wins.
The set functions as intended, then successfully pivots in on Vaporeon throughout a match thanks to Leftovers
I got a replay where my opponent forfeited turn 3 vs it but that's not very interesting.




Runerigus isn't anywhere near as awesome as the bug, but it still does its job very respectably and I can't really think of a better option for what it gets done. Being able to take on threats like Toxtricity, Cobalion, and Gigalith and check Heliolisk and Machamp in a pinch is very useful and it does this all while setting up Stealth Rock, hitting respectably hard and spreading burns. With the stuff it can help deal with it pairs immensely well with Mantine, who in return can take on most Ice and Grass moves thrown in Rune's direction, and with the addition of Umbreon results in a really solid backbone that I've enjoyed using and abusing. I also ran a Trick Room variant that gets up Stealth Rock and Mementos out just like its Unovan cousin, but with the benefit of still answering the aforementioned threats. Trick Room isn't very good at all, but I still got a few fun games where Rune filled its basic role.
Replays
Runerigus repeatedly checks Cobalion throughout the match
Wandering Spirit allows Rune to switch in on Incineroar and set up Stealth Rock, giving Necrozma safer entry.
Runerigus counterleads Cobalion, setting the stage for an easy Metronome Araquanid sweep later on.

 

[Daiyaga]

And that's another week over. Congratulations to Slowpoke92i for winning this fifth week !

Substitute + Toxic Araquanid got a lot of love from everyone who tried it for its ability to get rid of the few reliable defensive answers to Araquanid while still keeping Araquanid's defensive utility from its typing, bulk and ability intact. Eve and A Cake Wearing A Hat tried different filler moves on the last slot, with Protect allowing Araquanid to scout moves from choice-locked Pokémon that may force it out like Heliolisk while racking up Toxic damage, and Leech Life giving it additional staying power and letting Araquanid get rid of Celebi.

Runerigus on the other hand got some mixed feedback. Researchers pointed out how it fills unique defensive roles thanks to its typing and bulk letting it spinblock pretty reliably and at the very least soft check a good variety of pokémon like Lucario, Toxtricity, Cobalion or Gigalith, and its ability lets it neutralize threats like Machamp or Haxorus by sacrificing itself. Its movepool also proved to be pretty solid, with access to both Toxic Spikes and Stealth Rock, Will-o-wisp and the rare combination of Trick Room + Memento making it an effective Trick Room setter. Its lack of recovery meant, however, that it could struggle doing its job in the long run, and its low damage output prevented it from reliably keeping its entry hazards on the field against the numerous defoggers of the tier. It was still worth using, and fills a unique niche in the tier.

Next week's picks :

Whimsicott

Whimsicott @
Ability :
EVs :
-
-
-
-

Belly Drum Slurpuff

Slurpuff
Ability: Unburden
EVs :
- Belly Drum
-
-
-

Whimsicott is a pokémon that saw some usage in the early stages of the metagame, but has quickly fallen out. With Pokémon Home giving it some moves back, and the tier shifts that happened since its drop, we want you to test it out and see how well it fares in this new environment.

Slurpuff is another pokémon that quickly dropped through the tiers as it was lacking its main tool in the previous generations, Belly Drum. Pokémon Home brought that move back to its movepool, so we decided to give it a chance at the spotlight.

In order to participate you must do the following:

• Post here with a fresh RW alt (such as SSRW6 Daiyaga or SSRW6 Cake) and the name(s) of the Pokemon you will be using.
• Use at least one of the Pokemon being researched.
• Post your experiences with the Pokemon you're using, participate in the discussion!
• Post logs of this Pokemon in action against other teams - don't just tell us, show us
• The winner of the challenge will be the person who has the highest ladder ranking on the Pokemon Showdown UU ladder with their RW alt at the time the challenge ends. Winners will also receive a permanent spot in this thread's Hall of Fame.

This week will end on Sunday, March 29th at 11:59 GMT -6

 

[Eve]

signing up as SSRW6 Cotton to use both!

 

[KSt3ve]

SSRW6 frigo

Whimsicott

 

[WMAR]

SSRW6 WMAR

Whimsicott

 

[Xilefi]

SSRW6 Mouse

Whimsicott

 

[Daiyaga]

Reminder that we need you to write down your thoughts about the picks before the end of the week.

Xilefi WMAR KSt3ve Eve

 

[KSt3ve]

Moute²'s waifu (Whimsicott) @ Pixie Plate
Ability: Prankster
EVs: 48 HP / 252 SpA / 208 Spe
Timid Nature
- Moonblast
- Encore
- Substitute
- Knock Off

my team : https://pokepast.es/2108e357a499f3e1

I play with this Whimsicott set, the idea is to just overtake the pokemons with 350 in speed (espeon ...). The rest in pv to tanker more easily the attacks. Sub + again is formidable against ho. It can surprise goli if he uses First Impression or Spikes. Knock Off is very useful to remove the boots on inci, for chandelier and many other threats for the team.

Pixie Plate makes it possible to turn this average pokemon offensively into a threat not to be underestimated, because with a good speed and a very powerful moonblast with the combination of Substitute, I already have 6-0 several teams.

The general idea of the team is to win with reuniclus, Whimsicott, and this set in particular, seems to me to be the best choice.

 

[Xilefi]

Back when I discovered our beloved Showdown!, I had a ton of fun with Prankster mons in Gen 6. At these days, I didn't know anything about in-depths strategy but it is for obvious reason I wanted to use one of the cutter mon we have in name of Whimsicott. I absolutely wanted to use Prankster, where Infiltrator and Chlorophyll are good abilities, they don't seem appealing to me with the 77 base SpA which Whimsicott got. But there is the rub : I got pranked by -6 priority Trick Room ! After this deceiving and disappointing fealing of being pranked, I have been persisting with Trick Room that I've been using for the first time, thinking Whimsicott still fits in Trick Room. Though, I really think it has some arguments in UU right now.

First of, Whimsicott can sort of switch into all dragons with have besides Hurricane/Air Slash Noivern. Being a Fairy type which resists to Flygon EQ (if not running Fire Punch), to +1 Haxorus EQ and CC (not running Poison Jab) and threatening Moonblast to these prominent threats is awesome. More, being a fairy type in UU nowadays is awesome : being able to pivot on dragon, fighting and Knock Off dark moves with one mon is a bless (the only fairy type mons we have right now are Ribombee, Gardevoir and G-Weezing and only the last one can be called a pivot). Even better, being a Grass type isn't a liability as it provides switch into Bulky Water types, Rhyperior, Gigalith not running Heavy Slam, Rotom-Mow (and low-key Volt Switch mons) this gen in current UU. All thanks to U-Turn. Plus, Grass/Fairy is a fairly good double type. I want to give an honorabled mention to the Choice spec. which makes Whimsicott a decent revenge killer in addition of being able to 2HKO Umbreon.

some calcs

252 SpA Whimsicott Moonblast vs. 0 HP / 4 SpD Flygon: 264-312 (87.7 - 103.6%) -- 56.3% chance to OHKO after Stealth Rock
252 SpA Whimsicott Moonblast vs. 0 HP / 4 SpD Haxorus: 294-348 (100.3 - 118.7%) -- guaranteed OHKO
252 SpA Whimsicott Moonblast vs. 0 HP / 4 SpD Goodra: 152-182 (47.3 - 56.6%) -- guaranteed 2HKO after Stealth Rock
+1 252 SpA Whimsicott Moonblast vs. 252 HP / 252+ SpD Umbreon: 198-234 (50.2 - 59.3%) -- guaranteed 2HKO after Stealth Rock and Leftovers recovery

252 Atk Flygon Earthquake vs. 0 HP / 0 Def Whimsicott: 78-92 (29.8 - 35.2%) -- 19.4% chance to 3HKO
252 Atk Choice Band Mold Breaker Haxorus Earthquake vs. 0 HP / 0 Def Whimsicott: 102-121 (39 - 46.3%) -- guaranteed 3HKO
252 Atk Choice Band Mold Breaker Haxorus Close Combat vs. 0 HP / 0 Def Whimsicott: 123-145 (47.1 - 55.5%) -- 74.2% chance to 2HKO

Secondly, Whimsicott has a wild utility move pool working wonderfully with prankster : Memento, Trick, Stun Spore, Defog, Encore, Leech Seed, Substitute, Taunt, Tailwind ! You can literally tailor Whimsicott for the sake of your team.

As i said above, I've tailored Whimsicott for Trick Room, using its ability to pivot on many mons to (re)setup the Trick Room. Here are the set and the team I've used this week :

Whimsicott

@ Sitrus Berry
Ability: Prankster
EVs: 252 HP / 4 SpA / 252 Spe
Timid Nature
- Moonblast
- Memento
- Trick Room
- U-turn
Max HP and Sitrus Berry are mainly for longevity (for example, to avoid being 2HKO by Milotic/Vaporeon Ice Beam) and insure that Trick Room resolves.

WhimsicotTrick Room

https://pokepast.es/080835641051c544

The team is fairly standard as Trick Room is kinda obvious, and Whimsicott with Prankster Memento is used as a support for its mates or helping reset the Tick Room.

Trick Room+Memento showcase

https://replay.pokemonshowdown.com/gen8uu-1086633969
https://replay.pokemonshowdown.com/gen8uu-1087339689

The most interesting thing with Whimsicott in Trick Room to me is how using U-Turn : out the trick room, it plays normally but in trick room, Whimsicott is able to provide a slow U-Turn being able to pivot without sacrificing itself with memento in addition of scouting, keeping it as a sac or a final memento.

slow U-Turn showcase

https://replay.pokemonshowdown.com/gen8uu-1086842618

After some tweeks, the team exceeds my expectations (I forgot at the beginning to use an alt ) :

Even though I'm not sure Trick Room is where Whimsicott fits the most, I'm kinda confident now Whimsicott has its place in UU, as I just showcased how Prankster is as expected a great ability.