Antasma

Antasma is the (supposed) primary antagonist in the upcoming game Mario & Luigi: Dream Team. He is some sort of king who destroyed the Darkstone in order to create chunks that froze the Pi'llows. It's not yet known why he did this. Mario and Luigi are tasked with rescuing the Pi'illows which Antasma froze. His appearance gives the impression of it as a nightmare which the Pi'illows fear. Antasma can turn into a bat, this ability is similar to one of Cackletta's attacks. He can also possess beings, as seen when he enters Bowser's body.

Trivia

 * Antasma seems to bear similarities in appearance to all of the previous antagonists in the Mario and Luigi series. (Cackletta, Elder Princess Shroob, the Dark Star and Dark Fawful.)
 * Antasma's name is likely derived from the Greek word φάντασμα (phantasma), meaning "phantom," "apparition," or "ghost."
 * Antasma is the first antagonist that possesses Bowser at somepoint at the beginning of the game.