I posted this on Reddit a while ago, and it didn't exactly get much traffic, so I figure that it would be ok to just copy and paste that post here: "As most people who have played VGC this year have noticed, Celesteela is one of the bulkiest Pokemon in the entire metagame. As many have hard times dealing with this Pokemon, I decided to run every legal Pokemon through damage calcs in order to figure out everything that can OHKO max hp Celesteela with max defenses and a positive defensive nature for whichever type of attack I'm calculating against it. My results can be found here. To view this information properly, copy/paste everything from the pastebin into the backup/restore section of Pokemon Showdown's team builder. These calcs don't take into account boosting moves, such as dragon dance or nasty plot, nor do they take the ability analytic from Porygon Z or Starmie into account. Obviously, if they were taken into account, a lot of stuff would KO mons a lot earlier. I also nicknamed a Pokemon to note whenever the move it's using is boosted by either weather or by electric terrain, as well as giving a pokemon HP EVs to signify the percentage with which the weakest move provided in a set will OHKO Celesteela. If no HP EVs are provided, then it's a guaranteed OHKO, and if the attacking ev provided is less than maximum, then that means that those are the minimum evs required to OHKO. Hopefully this gives some people an easier time accounting for Celesteela when team building. Happy testing."