Ability ⇢ Neutralizing Gas
As long as this Pokémon is in the Active Spot, your opponent’s Pokémon in play have no Abilities, except for Neutralizing Gas.

{D} → Severe Poison
Your opponent’s Active Pokémon is now Poisoned. Put 4 damage counters instead of 1 on that Pokémon during Pokémon Checkup.