Qwilfish

The small spikes covering its body developed from scales. They inject a toxin that causes fainting.

Ability — Poison Point: If this Pokémon is in the Active Spot and is damaged by an opponent's attack (even if it is Knocked Out), the Attacking Pokémon is now Poisoned.

Venoshock (10+): If your opponent's Active Pokémon is Poisoned, this attack does 60 more damage.