Darkrai

Art from D/P.

Darkrai (ダークライ,Dākurai) is a legendary Pokémon resembling a dark, sinister ghost, such as the Grim Reaper. The top of its body is connected to the lower half by a tiny waist, giving it a figure shaped like an hourglass. A white substance flows from its head, obscuring much of its facial features. Its club-shaped arms are clawed and look muscular, with parts of them appearing tattered. Darkrai possesses the power to lure people into deep sleeps and show them dreams. Darkrai resides on Newmoon Island, and on nights of the new moon, when it is active, it shows horrible nightmares.

In 'Super Smash Bros. Brawl'

Darkrai is set to appear in Super Smash Bros. Brawl, as seen at Whobby 2008, it is unknown of what it does yet.