Qwilfish

Whenever a Pokémon an opponent controls deals damage to Qwilfish, or an ability of that Pokémon puts a -1/-1 counter on Qwilfish, create a Poisoned token attached to that Pokémon.

Venoshock - {w}{w}, {t}: Put a -1/-1 counter on target Pokémon. If that Pokémon has an aura attached to it named Poisoned, put two -1/-1 counters on it instead.

"They inject a toxin that causes fainting."