Well I got a dm from someone who will remain anonymous as he didn't tell me whether he wanted to be credited or not (if he says he wants credit I will edit this). Anyway the pokemon I shall talk about is maushold.
Personally I am not that experienced in the art of the maus but I have played against it plenty of times so I shall explain my opinions based on that. I think maushold is an ok pokemon on offense but it isn't super viable thanks to some very...VERY exploitable weaknesses.
Maushold has a decent stat spread of a mediocre 75 attack 74 hp 70 defense 75 special defense and a solid 111 speed. It's main strengths are its hidden ability technician and its moves tidy up and population bomb.
I feel like most people who play competitive pokemon know what technician is so I won't bore you with an explanation. Tidy up is a move that not only increases your attack and speed by one stage but also clears hazards making maushold a strong hazard removal pokemon. Finally population bomb is a 20 bp (30 bp with technician) move that hits the opposing pokemon 10 TIMES! That is a 300 bp move and that isn't even including stab or a tidy up boost.
This may sound amazing but there is a reason it is ranked ru. First off while its speed would be really good in say...Gen 8 the insane amounts of speed power creep make maushold look like macargo while deoxys speed looks like...deoxys speed. That combined with its meager defenses makes maushold easy to kill by faster by pokemon before it can set up. Even if it does set up it can still be killed easily by powerful priority users like e killer dragonite lokix kingambit etc.
Second off population bomb while powerful has one fatal flaw. It is a contact move which means it is susceptible to abilities like flame body static and rough skin as well as items like rocky helmet...and sticky barb I guess?
Finally it is a normal type using a normal type move which means it is decimated by fighting types (aka just zamazenta) resisted by steel types and has no effect on ghost types.
This may sound like I am making maushold out to be completely unusable but it does have other useful tools. It can go tera dark tera blast to counter ghost types (though I wouldn't advise this as you are better off saving that position for something better and it won't do that much damage). It also has encore which means it could trap an unsuspecting set up sweeper looking at maushold as an easy kill.
All in all maushold is a strong offensive mon with a lot of unique tools. However it has a myriad of easy to exploit weaknesses that prevent it from being ou (or even uu) proper. Tell me your thoughts on maushold below as that ends the first edition of...whatever this series is going to be called. I will be taking more requests tomorrow so byeeee
Maushold mentioned, my love of low-BST mons that still find a use in OU has been activated.
Maushold has a love/hate relationship with Kingambit; as much as it hates Kingambit coming in and forcing a guessing game with Sucker Punch, it also loves coming in after a Sucker Punch KO and clicking Encore for safe setup, which largely neutralizes last-mon Kingambit. This does mean Kingambit can be next-to-last mon, but depending on what else they have, there's a good chance a +1 Maushold can just kill the other stone dead.
After all, Population Bomb is insane.
A few demonstrative calcs said:
252 Atk Technician Maushold Population Bomb (10 hits) vs. 252 HP / 252+ Def Dondozo: 240-280 (47.6 - 55.5%) -- approx. 60.9% chance to 2HKO
That's right, better-than-even odds of killing 252/252+ Dondozo, from full in two turns, so Dondozo is a risky switch in, needing to predict whether you'll go for the Tidy Up or just attack directly.
+1 252 Atk Technician Maushold Population Bomb (10 hits) vs. 244 HP / 36 Def Gliscor: 420-490 (119.3 - 139.2%) -- guaranteed OHKO
Gliscor can't switch in, and if you pivot into either Spikes or Swords Dance, that's free setup.
I'm also a fan of Tera Dark over Tera Ghost, because Tera Dark Maushold can survive a +0 Five Fallen Sucker Punch from 252+ Kingambit, and if it didn't have to switch into too many hazards, it can live an Iron Head, too. Being able to live a Sucker Punch and threaten an Encore means that you can guarantee some solid damage on Kingambit, not needing much chip to KO if it terastalized out of the Steel typing.
I also like Tera Dark because it gets around ghosts pretty nicely; +1 Tera Dark Bite is a 2HKO on Gholdengo, for example. This works nicely with ID/BP Zamazenta, as the opponent has to pick their poison: do they use their ghost to stop Maushold and allow Zamazenta to get past easier with Crunch, or do they preserve their Zamazenta counter and trade something else for Maushold?
All that said, it has two major weaknesses that have to be accounted for, and one especially challenging matchup:
1) Rocky Helmet. This NEEDS to be Knocked before Maushold can pose much of a threat, and forcing in the Rocky Helmet mon to get Knocked can be difficult. Falling back on Tidy Up/Encore means that Maushold won't be entirely useless, but without Population Bomb it's pretty grim.
2) Flame Body - so currently Moltres, but also Volcarona if it comes back after a Tera Blast ban and the odd Talonflame on stall. Tera Fire is the only response, and that's otherwise mostly useless, Maushold already does pretty well into most Wisp users.
The problematic matchup is HO. Maushold is fragile and can't wear HDB, so an HO team can be rough, both to bring it in and because they can outspeed even after a Tidy Up with Booster Speed. It's not hopeless, Population Bomb is powerful enough that just attacking immediately can work out well and, push comes to shove, Tidy Up does clear hazards, but it's difficult.
PS: +1 Maushold is
just barely not an OHKO on hazard setting Ting-Lu with just SR, and favorable to kill with a single layer of spikes instead, so it's a possible option to break a Zapdos-Glowking-Ting Lu core.