Antasma

Antasma is the supposed primary antagonist in the upcoming game Mario & Luigi: Dream Team. It is a nightmare who apparently destroyed the Darkstone in order to create chunks that froze the Pi'illows. Mario and Luigi are tasked with rescuing the Pi'illows which Antasma froze.

Trivia

 * Antasma seems to bear similarities in appearance to all of the previous final bosses in the Mario and Luigi series. (Cackletta, Elder Princess Shroob, and the Dark Star.)
 * Antasma's name is likely derived from the Latin word phantasma, meaning "spectre" or "apparition."