Antasma

"SCREEEK! I vanted to steal Peach's power...But I changed my mind! You are much stronger...and evil! SCREEEONK! Vork with me! SCREEEP!"

- Antasma

Antasma is the main antagonist in the Nintendo 3DS game, Mario & Luigi: Dream Team. He is described as some sort of bat king who stole the Dark Stone in order to fullfill his dreams. After the Pi'llows managed to defeat him and imprisoned him into the Dreamworld he shattered the Dark Stone. 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 Antasma'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 Antasma possessing Bowser while Bowser is trying to kidnap Peach and then using him to attack the brothers. While possessed, Bowser gains a purple aura somewhat similar to Shrowser's distorted coloration, and Antasma 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.

History
Antasma first appears, albeit silent and not referred to as such, on the blimp ride to Pi'illo Island as an unwanted passenger sent by Dr. Snoozemore for unknown reasons (although it's implied that this appearance is but a hallucination by Luigi). He replaces Bowser from previous games as the tutorial boss, and like Partners in Time and Bowser's Inside Story, Toadsworth is there to assist Mario. His only attack is to transform into a swarm of bats, which fly at Mario, but doesn't cause any damage. As such, like Bowser, he will be defeated in a few turns.

This is far from his demise, however, and after being "defeated", he curses the blimp so it crashes into Pi'illo Blimpport, which luckily for them, happens to be their destination. However, Luigi faints of panic, and Broggy falls to parts unknown because of this. It's not long before he shows up again, this time possessing Broque Monsieur, who gave up his entrepreneuring from the previous game in favor of being a Pi'illo Island tour guide. He summons monsters for Mario to fight, not unlike Kamek in Partners in Time. Eventually, Antasma leaves his body and Broque dismisses the torturing as a show.

Antasma is not seen again until after Dreambert's pillow is found and Luigi sleeps on it, opening a portal to the Dream World. He calls out to Princess Peach in an effort for her to approach the portal, and proceeds to suck her in. Mario loyally gives chase, but Antasma distracts him with a dream counterpart of him and makes a beeline for Dream's Deep. However, Mario manages to save Dreambert, who explains how Antasma shattered the Dark Stone, an ancient power of Pi'illo Island, and managed to turn the Pi'illo people to stone.

With the help of Eldream and his pet, Dreambunny, Mario manages to reach Dream's Deep, which is actually filled with his greatest nightmare--Mario leaving him behind. However, Bowser, enraged that someone else besides him had kidnapped Peach, also ends up there. When Mario, Dreamy Luigi, and Dreambert reach Antasma, Bowser swats him in rage. He then leeches Bowser's face, when he is first seen speaking. He says that he kidnapped Peach in hopes of using her power to take over the real world, but it would be more useful to use that of an evil creature, offering for them to team up. Bowser disagrees, taunting his accent. But when he makes a deal with Bowser, that after they take over the world, he can keep Peach all to himself, and using his powers, they can defeat the Mario Bros., he reluctantly agrees. Antasma then possesses Bowser, and the two fight Mario and Dreamy Luigi and barely win. Antasma says it'd be best if they go and take over the real world first, then kidnap Peach.

Eldream and Dreambunny escort the Mario Bros. and the princess out of the Dream World, and think they've won, but then Dreambert and Starlow reveal that Antasma is still on the loose, along with Bowser, and explains the same story he told earlier to Peach. Now Mario and Luigi must find the Dream Stone, the only thing that can counteract the Dark Stone.

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".
 * Antasma's is much larger in-game than as shown in his artwork.
 * Antasma has many similarities with Count Dracula. Antasma speaks with a Slavic accent, similar to Dracula. Also note that Dracula is a vampire and can transform into a bat. Antasma is a ghostly bat king and can also transform into a bat.
 * In some translations, Antasma is called a count instead of a king, just like Dracula. Antasma's Russian name, Mrakula, is even a play on Dracula's name.
 * Unlike the other tutorial bosses in the Mario & Luigi series, Antasma has his own music instead of the "normal battle" theme.