Thomas and Twilight Sparkle's Adventures of Monsters vs. Aliens is an upcoming Thomas/MLP/DreamWorks Animation crossover to be created by Hiatt Grey.
On the day of her wedding to news weatherman Derek Dietl, Susan Murphy is struck by a meteorite and its energy causes her to suddenly grow over fifty feet in height during the ceremony, ripping her dress. She is tranquilized and awakens in a top secret government facility that houses monsters without human knowledge. She meets the warden W.R. Monger, and fellow inmates: Dr. Cockroach P.H.D., a mad scientist who became half cockroach after an experiment; B.O.B. (Benzoate Ostylezene Bicarbonate), a brainless, living mass of goo as a result of a food flavoring mutation; Insectosaurus, a mutated bug standing at over 300 feet in height, and The Missing Link, a prehistoric fish man who was thawed from deep ice; and Susan herself has been renamed to Ginormica. Meanwhile, in deep space, an alien named Gallaxhar is alerted to the presence of quantonium; a powerful energy source on Earth, and he sends a probe to retrieve it. After the probe crash lands on Earth, the president attempts to make first contact with it by playing a keyboard version of Axel F, but it begins to rampage toward San Francisco.
Monger arranges for the freedom of the monsters if they can stop the probe and the president agrees. The robot detects the quantonium radiating through Susan's body and tries to take it from her, putting many lives in danger. The monsters work together to save the people and defeat the probe. Not to be deterred, Gallaxhar sets course for Earth to obtain the quantonium. Meanwhile; the now-free Susan returns home with her new friends and reunites with her family, but the monsters alienate themselves from the humans due to their inexperience. Susan meanwhile, meets with Derek, who harshly breaks up with her due to her new status, which may overshadow him and his career. Heartbroken, the monsters reunite, but Susan realizes her life is better as a monster and promises not to sell herself short to anyone again. Suddenly, Susan is pulled into a large space ship. Insectosaurus tries to save her, but he is shot down and supposedly killed by the craft's weapons.
In the ship, Susan breaks free of her captivity and chases Gallaxhar until she is trapped and the quantonium is extracted, returning her to her normal size. Gallaxhar then begins making clones of himself in order to launch a full-scale invasion of Earth. Outside, Monger picks up B.O.B., Cockroach and Link, and manages to get them on board the ship. They rescue Susan and make their way to the main core where Cockroach sets the ship to self-destruct to prevent the invasion. All but Susan are trapped as the blast doors close and she goes to confront Gallaxhar on the bridge. With her time running out, she sends the ball of stored quantonium down on herself, restoring her monstrous size and strength. After rescuing her friends, they flee the ship and meet with Monger, riding Insectosaurus, who now has the wings of a butterfly after having been in a cocoon following the attack. As they flee, the ship self-destructs with Gallaxhar and his army still on board.
Returning to Modesto, Susan and the monsters receive a hero's welcome. Derek, hoping to take advantage of Susan's fame for his own career tries to get back together with her, but she rejects him before a television audience. Monger then arrives, telling the monsters about a new monstrous snail called Escargantua making its way to Paris. The group then climbs on Insecto, who flies away from the scene as everyone bids them farewell and a safe trip.
- Knockout, Puffer, Dolphy, Rachel, Mighty Joe, Daylight, Jenny, Pete, Kevin, Joe Lamb, Alice Dainard, Charles Kaznyk, Cary McCarthy, Martin Read, and Preston Scott guest star in this film.
- Alter, Samantha and Slate, and Queen Chrysalis will work for Gallaxhar in this film.
- Thomas & Friends: Hero of the Rails and Monsters vs. Aliens were both released in 2009.