252+ Atk Strong Jaw Dracovish Fishious Rend (170 BP) vs. 188 HP / 236+ Def Shiinotic: 150-177 (48.7 - 57.4%) -- guaranteed 2HKO after Stealth Rock and Leftovers recoveryI have already stated my opinion so I won't do so again, but I would like to present this:
Effect Spore, Bold Nature, Leftovers, 188 HP, 236 Def, 80 SpAtk, 4 Speed, Max EVs
I tried this set out in three battles with Vish, only one of which I actually got to use it, I switched it in against a Fishious Rend, it did around 70%, which let me know it was banded instead of scarfed, and effect spore paralyzed it, in the end, he switched Dracovish out when in was under 5% and paralyzed, basically removing it.
Now this can be used as a pro or anti ban argument, on one hand it's a counter that can help contain Dracovish, on the other hand, it's SHIINOTIC. IN WHAT WORLD COULD SHIINOTIC HAVE A NICHE IN OU?
I had a lot of trouble getting the exact numbers for the set, even with max special attack (with neutral nature) it will never have a 50% chance to OHKO.
This set has so many variables that you can adapt for what your team needs, I tried to EV it so it could take two hits and severely weaken it, or even kill if effect spore came in clutch. Really it's up to you. The biggest variable is whether you go with Leftovers or Rocky Helmet, Leftovers allows for a guaranteed hit on Dracovish (barring a crit), while Rocky Helmet allows for Shiinotic to kill after helmet damage. I think it's pretty much mandatory to have a +defense nature on this, so I didn't even try outside of +defense. What it lowers is up to you, you can lower attack, or you can lower speeds and counter trick room teams, I chose -Attack, in fact, I even threw in a few speed EV's just in case other base 30's would make an appearance, I know there aren't many, but it's not impossible to see Galarian Corsola or Snorlax.
This set also does surprisingly well in battles without Dracovish, ok, well isn't the right word, it's more like not completely dead weight. Strength Sap allows for it to switch into physical attackers (with correct prediction) and weaken them while healing damage that was taken beforehand.
Some calculations (With presented set unless otherwise stated)
48.7-57.4% for every fishious rend, with leftovers and protect afterwards, 36.2-44.9% lost if max damage done, only 30% chance to kill, 0% chance when Shiinotic is at 58% or higher, in other words ridiculously low chance to kill (barring crits)
73-85.7%, 60.5-73.2% after leftovers and protect, guaranteed 2HKO, which is bad, but let's be honest, that power is absurd, so everything has a hard time killing it.
Shiinotic Moonblast, 77-91.3%, guaranteed 2HKO, but remember, I didn't put that much into Special Attack so:
252 SpAtk EVs Shiinotic Moonblast 90-106.8%, 43.8% chance to OHKO (With +SpAtk nature is 93.8% chance to OHKO, but this isn't about OHKOing, it's about removing Dracovish as a threat from the battle)
0 SpAtk EVs Shiinotic Moonblast 69.6-82.6% 2HKO, run for maximum bulk
The most pivotal calculation: 51% chance for Effect Spore to take effect The implications for this are huge
Poison - Either kills it at the end of poisoned turn, or makes it dead on arrival assuming my chosen EV's, probably the smallest out of the three.
Paralysis - Chance for Shiinotic to kill if paralysis works out, and essentially guarantees everything will outspeed it, which is huge.
Sleep - Puts Dracovish out of commission for several turns, either forcing a switch, or a free strength sap and another move to kill for Shiinotic
Not to mention if it takes 3 hits the odds increase to 65.7%
To finish this off, I know it's not a 100% check, I know it won't always do what's intended, but the only reason I wrote this was because this set can be adapted in so many ways, so I think unpredictability will be the reason this becomes viable in any amount. Finally, I don't think this will be good, it's just an idea.
Nuff said. Also, I have no idea why you slash Helmet when it needs the Leftovers recovery to be able to switch into Scarf Vish, and needs to be close to full health too.
And the fact it always gets 2HKOed by Banded Vish... Not to mention:
252+ Atk Strong Jaw Dracovish Fishious Rend (170 BP) vs. 188 HP / 236+ Def Shiinotic in Rain: 225-265 (73 - 86%) -- 81.3% chance to OHKO after Stealth Rock and 1 layer of Spikes (same calc applies to Choice Band).
Even assuming max Def:
252+ Atk Strong Jaw Dracovish Fishious Rend (170 BP) vs. 252 HP / 252+ Def Shiinotic: 147-174 (45.3 - 53.7%) -- 91.8% chance to 2HKO after Stealth Rock and Leftovers recovery
252+ Atk Strong Jaw Dracovish Fishious Rend (170 BP) vs. 252 HP / 252+ Def Shiinotic in Rain: 221-261 (68.2 - 80.5%) -- 43.8% chance to OHKO after Stealth Rock and 1 layer of Spikes
If you're going to sac a mon to deal with Dracovish, I recommend Destiny Bond so you're only giving up a moveslot on a mon rather than a whole mon.
And remember fellow theorymonners, calc WITH ROCKS UP. That is all.