Antasma

Antasma is the (supposed) primary antagonist in the upcoming game Mario & Luigi: Dream Team. She is a being who destroyed the Darkstone in order to create chunks that froze the Pi'llows. It's not yet known why she did this. Mario and Luigi are tasked with rescuing the Pi'illows which Antasma froze. Her appearance gives the impression of it as a nightmare which the Pi'illows fear.

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 Fawful.)
 * Antasma's name is likely derived from the Greek word φάντασμα (phantasma), meaning "phantom," "apparition," or "ghost."
 * Antasma can apparently turn into a bat, as shown by the cover for the game. This ability is similar to one of Cackletta's attacks.