Unicron

The biggest Transformer ever. This robot is completely evil and is big. Don't like Unicron? Tough, he'll just eat your planet. That's right, this guy is a planet that thinks nothing of munching on other planets and moons. And then if that wasn't enough, he can just transform into a giant robot and start kicking ass all over. It seems that Unicron can only be defeated with the Autobot Matrix of leadership, as seen in Transformers: The Movie.

Massive planetoid Transformer that is essentially the embodiment of evil in the Transformers' universe. According to the varying story lines, Unicron exists as a sort of multi-universal being. Meaning that he may be temporarily destroyed in one reality, but is omnipresent in essence.
His most recent appearance (that I am aware of) was in a somewhat weakened state, being an extremely powerful tank-like Transformer, rather than a demonic planet omnigod.

Big, Shaq sized Transformer who eats up any planet or moon in it's path. Basically the baddest mofo in the universe. He has a "planet mode" in which he consumes planets and also a robot mode. First appearance was in the 1980's Transformers Cartoon Movie, in which he rebuilt a defeated Megatron into Galvatron, and in return he made Galvatron his bitch. But at the end of the film Hot Rod turned into Rodimus Prime via The Matrix (Allspark in live movie) and Rodimus used The Matrix to destroy Unicron.
Unicron better appear in the next live movie.
Also note that Unicron had epic voice. And oh ya, the movie takes place in the year 2005, so it all happened 2 years ago...
Unicron:"For a time…I considered sparing your wretched little planet Cybertron. But now, you shall witness...its dismemberment!"

Ginormous robot featured in "Transformers: The Movie." A large metal robot, Unicron is extremely large and devours planets for sustinence. In the comics, he is the embodiment of a dark god who destroyed the universe prior to the big bang. In the American cartoon continuity, he was developed by the alien Primacron. Unicron's only known weakness is the Autobot Matrix.

1.(Pronoun) The largest of all known Transformers. Often portrayed as a bringer of death and destruction. Has destroyed many planets to feed his never ending hunger for energy. Although immortal, body can be destroyed by immense power....that is only found in the Autobot Matrix of Leadership.

First Appearence: August 2nd, 1986
First Death: August 2nd, 1986 (killed by Matrix)
Reappearence: Late 2004/Early 2005, Transformers Armada and later Energon.
Re-killed: Late 04/ Early 05. Destroyed by the Matrix in Armada, body possessed by Megatron which is later destroyed by Optimus Prime powerlinked to Omega Supreme.

legendary robot from the transformers movie,is now appearing in transformers armada although i havent seen what he looks like,was voiced by orson welles in the movie who died soon after,a fiting end that it should be his last film.

a big-ass mother fucking planet eater, and he will eat your planet like fucking popcorn! this fat bastard literally floats through space, I mean look at this hungry cunt!