Darkrai

Darkness 80 HP Stage: Basic Rare Holo

Dark Slumber

At the end of your opponent's next turn, the Defending Pokémon is now Asleep.

Dk Dk N

Dark Resolve

If the Defending Pokémon is Asleep, remove 4 damage counters from Darkrai.

Poké-Power Darkness Shade

Once during your turn, when you put Darkrai from your hand onto your Bench, you may choose 1 of the Defending Pokémon. That Pokémon is now Asleep.

It can lull people to sleep and make them dream. It is active during nights of the new moon.