Unbeatable almost

[Super Sonik]

wabbufet ex




HP 140

POKEPOWERthis pokemon cant take damage in any way

no atacks

retreat cost 9


it can be taken down by voltorb with swift :D

[yoshi1001]

Yawn. Insanely broken, though Muk kills it.

[GuardianTIM]

Let's not forget Dusclops with Judgement. It doesn't do damage, but KO's them instantly.
Also, anything with Feint Attack or Swift (both attacks ignore effects on the defending Pokémon) can knock it out after a few turns.