I can't even belive someone suggest RBY Mewtwo is not ill broken and godly OP.
Let's see why he is OP:
- He can just OHKO anything that its coverage can make a SE.
- He can just OHKO everything with 2+ Psychic, bar Chansey and other Psy pal.
- 25,4% of critical just if you're too lazy to use Amnesia.
...on a game where non even Hyper Beam Snorlax can archive such godly archivement.
- At the same time, he's part from the best type of the game: Psychic.
- His physical bulk is superior to everything else, bar Cloyster, Onix, Golem, Rhydon, Slowbro, Lapras, Snorlax, by a minimal difference (less than 10%).
- His special bulk is superior to everything else by a huge distance (more than 25% of Exeggutor), bar Chansey.
In other words, the is THE supreme tank of the game and the same time, he is THE supreme powerhorse of the game, all in one, no weakness, this is even not taking in account him's moveset.
Now, by just that he is broken, but now let's look at him's moves:
- Barrier + Amnesia + Recover means you can't just KO it, he becomes literally and completely inmortal, unless your opponent is excesive highly lucky with criticals. When I mean excesive, I mean excesive, good luck with chances below 5% to actually archive the KO. In other words, all you have at your hands is the option to explode it (you'll only archive the KO if the explosion is also a critical) or just aim for the freeze (a thing that only a Chansey and other Mewtwo can try, protip: he'll win more offen against Chansey that Chansey against him). You can also aim for the paralyze: it can work but it usually doesn't, why? Simple: You're still needing a heck as hell of luck with the Criticals to archive the KO, with the paralyze you're just improving your chances 1,25 of chance to the already low 3-6%, and, yeah, paralyzed Mewtwo can't be frozen.
- STAB Psychic is just resisted by Psychic pals; no one of them can actually combat Mewtwo because their lower as hell special bulk, power and usually speed. All you can do is try luck with a Mew against sets without coverage or with Amnesia Slobro if he forgots Thunderbolt; no problem, Mewtwo stilll had farest superior chance to beat both even without coverage, thanks to its abussive 25,4% chance of critical and the special defense down of Psychic.
- Only if you want to do less-stally games, you can also forgoe Barrier and/or Recover for just perfect him's coverage. Thunderbolt and Ice Beam will OHKO everything that is weak to it and allow Mewtwo to participate on a freeze war against Chansey if he wants to (don't forget you don't have any need to keep your Mewtwo agaisnt Chansey all the time, you can just keep swithching and wasting the limited PP) and more important: against other Mewtwo.
- If you're feeling unlucky, you can also just put Selfdestruct and just blow the enemy Mewtwo, Mew or Chansey, still, it's usually just recomended once you defeated all the others Pokémon.
- If you're feeling lucky, you can just swap Ice Beam for Submission and aim for a OHKO against Chansey; even if you don't archive a critical, it will hard pressure Chansey to recover most of the time and she will just be unnable to freeze war you too much before eventually failing down. It can leave you prone to OHKO Explosions, so, take care.
- If you're bored, you can try almost any good set that is used on a OU Pokémon already, incluiding being a superior Tauros, superior Snorlax, superior Chansey, superior everything bar Sleepers and Wrappers (just because he doesn't have those moves).
Ah, and yeah, even when Wrap is powerful: it can't defeat Mewtwo, even if you're lucky (its not strange to be lucky with that thing), you can't KO it before running out of PP unless Mewtwo doesn't have any partner with him. And still, most of the time you'll need to explode something, that means he's going ALWAYS get a K,O, unless you do something I said before; freeze it, mirror him with other Mewtwo or being stupidly lucky with criticals.
Gosh, I don't even know why I'm wasting my time, it's obvious RBY Mewtwo is THE uber from all times, not even Kyogre is that good. I din't even talked about him's godly speed, he just tie with Jolteon and Aerodactyl and is surpassed by Electrode.
Oh, yeah, when counters/checks are not completely correlated to being OP and broken...
Hard Counters: Nope.
Soft Counters: If he's paralyzed... other Mewtwo or Mew and/or sacrificing most of your team for cheap damage if he doesn't have Recover, extreme luck.
Hard Checks: Nope.
Soft Checks: Chansey, Mew, ParaWrapper Dragonite, blowing your Snorlax while he's paralyzed, ultra-mega-extreme luck.
Mirror: Himself.