Antasma

Antasma is the (supposed) primary antagonist in the upcoming game Mario & Luigi: Dream Team. He is described as some sort of bat king who stole the Darkstone in order to fullfill his dreams. After the Pi'llows managed to defeat him and imprisoned him into the Dreamworld he shattered the Darkstone. The shards of the Darkstone turned all the Pi'llow they touched into stone. Mario and Luigi are tasked with rescuing the Pi'illows which Antasma froze, as well as Peach (who he abducts early in the game).

Little is known about Anastama's abilities at this moment, but it appears that Antasma can turn into a bat, not unlike what Cackletta's clones can do; on other occasions, he is seen as a cloud-like being, notably while he is carrying Peach. He can seemingly also possess beings, as both videos and pictures of the game show Antastma possessing Bowser while Bowser is trying to kidnap Peach while he is being used to attack the brothers; while possessed, Bowser gains a purple aura somewhat similar to Shrowser's distorted coloration, and Anastama surrounds Bowser in a large swarm of purple bats similar to himself during the battle. In all his forms, Antasma seems to be able to create powerful sonar beams which are both ear-splitting and able to destroy terrain.

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 word "phantasma", meaning "spectre" or "ghost".