Misdreavus

It loves to sneak up on people late at night, then startle them with its shrieklike cry.

Lullaby: The Defending Pokémon is now Asleep.

Nightmare Feast: If the Defending Pokémon is Asleep, this attack does 50 damage and remove 5 damage counters from Misdreavus. If the Defending Pokémon is not Asleep, this attack does nothing.