Qwilfish TRR 27

If Qwilfish is your Active Pokémon and is damaged by an opponent's attack (even if Qwilfish is Knocked Out), flip a coin until you get tails. For each heads, put 1 damage counter on the Attacking Pokémon.

Flip a coin. If heads, the Defending Pokémon is now Paralyzed and Poisoned.