Haunter

Ability · Hidden Poison

If Haunter is your Active Pokémon and is damaged by an opponent's attack (even if Haunter is Knocked Out), the Attacking Pokémon is now Poisoned.

P · C

Choose 1 of your opponent's Pokémon. This attack does 20 damage to that Pokémon. (Don't apply Weakness and Resistance for Benched Pokémon.)

Weakness: Darkness · Resistance: Colorless · Retreat: 1