Unicron

Unicron is a fictional villain from the "Transformers" media franchise. Designed by Floro Dery, he was introduced in the 1986 animated film ' and has since reappeared in ', ', ', ', ' and Atari's 2004 "Transformers" video game. Unicron is a prodigiously large robot whose scale reaches planetary proportions, and he is also able to transform into a giant planet. Unicron's origin has expanded over the years from simply being a large robot to being a god of chaos who devours realities. He often employs the help of Decepticons in his work, and in some stories is considered part of the origin of the Decepticon forces.
Fictional character biography.
According to the Transformers lore, before the dawn of time, Order and Chaos exist within an extra-dimensional entity known as The One. To explore the fledgling universe, he creates the astral being known as Unicron, and then subdivides him, creating his twin, Primus.
Physical dimensions.
Unicron's size is never specified in any canon materials, aside from the vague term "planet size". In "The Transformers: The Movie", Unicron's height appears to be anywhere from several kilometers (as when handling Galvatron) to several hundred kilometers (as when attacking and destroying Lithone and Cybertron's moons, and attacking Cybertron). A planet-mode diameter of has been suggested and robot-mode dimensions can follow from that estimate, provided that there is no change in size (compression or expansion) common among so many Transformers. One scene in the movie shows Jazz driving out of one of Unicron's eyes, just small enough to fit through them, though in another scene the Quintesson ship Hot Rod arrived in is tiny compared with the eye. Unicron is also small enough to stand on Cybertron's surface.
Animated series.
The Transformers.
The character Unicron first appears in the opening scene of 1986's "", immediately making clear his goal by consuming the small world of Lithone. Subsequently, when the Decepticons Megatron, Skywarp, Thundercracker, and the Insecticons are set adrift in space and left to die following a furious battle with the Autobots, Unicron appears before them and offers Megatron a deal: in exchange for a new body, and new troops, Megatron will destroy the Autobot Matrix of Leadership, the only thing that can stand in Unicron's way. Thus, Unicron rebuilds Megatron into a new and more powerful body and rechristens him to Galvatron. He then uses the battered bodies of the other Decepticons and creates Scourge, the Sweeps and Cyclonus. Unicron also gives Galvatron a vessel, and Galvatron begins to carry out his assigned task, although he is loath to do so. When Galvatron shows any signs of opposition to Unicron's will, Unicron inflicts agonizing torture in his mind to coerce him into obedience.
Following Unicron's consumption of Cybertron's two moons, Galvatron obtains the Matrix from Ultra Magnus, believing he can use it to bring Unicron under his control. Attempting to open the Matrix to intimidate Unicron, Galvatron only prompts his transformation into robot mode and is swallowed by the planet-eater. Unicron lays waste to Cybertron, halted briefly when the young Autobot rookie, Hot Rod, crashes a Quintesson spacecraft through his eye. Finding Hot Rod inside Unicron's body, Galvatron suggests an alliance against their common enemy. However, Unicron inflicts his mental torture upon Galvatron, forcing him to fight Hot Rod. Hot Rod seizes the Matrix from Galvatron during the fight and becomes Rodimus Prime. Rodimus throws Galvatron into space, freeing him from Unicron's mind-control. Rodimus opens the Matrix within Unicron, destroying his body, leaving only his head, which becomes a moon of Cybertron.
Unicron was voiced by Orson Welles.
The third season of "The Transformers" animated series continues Unicron's story where the movie left off, as the planet-eater's deactivated head settles into orbit around Cybertron. His head is visited by Cyclonus, who accesses the memory bank to discern the fate of Galvatron. Later, the ghost of the deceased Decepticon Starscream reactivates Unicron's head and enters into a bargain with him, performing three labors in exchange for the restoration of his body. Starscream (inhabiting and controlling Scourge's body) gathers for Unicron Metroplex's eyes (breaking one and replacing it with one from Trypticon) and Trypticon's transformation cog. He begins to connect his head to Cybertron, which would become Unicron's new body. Starscream demands that Unicron restore his own body so that he can complete the required connections. Once Unicron does so, Starscream double-crosses him and refuses to finish the job. Unicron's head is subsequently blown off into space by an explosion instigated by the Autobots.
Later, when searching for a new supply of positrons (anti-electrons), the Decepticons venture to Unicron's head, where Cyclonus and Scourge accidentally awake the slumbering demi-god. At the same time, Grimlock constructs the Technobots from pieces of Unicron's head, and one of their number, Strafe, severs enough of Unicron's neural connections to shut him back down.
Although Unicron himself does not appear again, his origin in the animated series is later revealed. Unicron was created near the beginning of the universe by the diminutive genius known as Primacron, who intended for him to devour all life in the universe, leaving a blank slate that Primacron could use as he saw fit. However, Unicron turned upon Primacron, deciding that "he" would rule the universe and subsequently set out to achieve that goal.
Unicron trilogy.
Unicron would appear in "Transformers Armada", voiced by Mark Acheson. In episode 23, several of the human allies discover Sideways within their computers, and attempt to stop him, but not before learning that his accomplice was Unicron within the mainframe acting as a failsafe. The final season depicts Unicron as the main antagonist. Called the "Unicron Battles", the Transformers Earth groups return to Cybertron. The humans learn Unicron had made the Minicons to take control of Cybertron, but the Minicons revolted and become part of the Transformers' own civil war. 
Unicron appears in the sequel series "", set 10 years after the Unicron Battles. The autobots successfully destroy Unicron, but Unicron manages to place his consciousness within Megatron. In the final episode, Megatron is corrupted by Unicron, leading to another confrontation with Optimus Supreme. Around this time, Primus, Unicron's sibling, creates an energon sun and attempts trap Unicron's soul with it. Both he and Megatron are destroyed for good, and the energon sun recreates Alpha's planets that were destroyed long ago.
"Aligned" continuity.
In the "" storyline, Unicron (voiced by John Noble) is the source of Dark Energon, a poisonous and corruptive form of Energon with the ability to revive the dead - albeit in a mindless, zombie-like "Terrorcon" state - also known by the name "the blood of Unicron". Unicron is believed to represent the Anti-Spark (most likely a counterpart of the AllSpark).
Publication history.
Fun Publications.
When Unicron attacks Cybertron in the midst of the chaos caused by a Mini-Con civil war, Sentinel Maximus and Omega Prime fight him off with the help of their allies. In the end Unicron is driven off, badly wounded, by Primus.
Unite Warriors.
In conjunction with the Unite Warriors line, Takara Tomy released a comic detailing how the Galvatronus combiner came to be. Following his defeat at the conclusion of "The Headmasters", Galvatron's icy tomb is discovered by Cyclonus, whose body Galvatron modifies to accommodate his own head in the chest compartment. Seeking a more fitting form, Galvatron directs Cyclonus to approach the disembodied head of Unicron, who is convinced to help Galvatron attain a combiner form with Cyclonus as its core. To accomplish this, Unicron opens dimensional rifts in order to bring Curse Armada Thrust, Zombie War Breakdown, and Wandering Roller into their world. To Cyclonus' surprise, Starscream makes an appearance, expressing interest in joining this new alliance. Unicron grants Starscream a new physical form, and Galvatron's head takes control of his new minions to take on his new form of Galvatronus.
Film series.
Debuting in "", the six horns of Unicron began appearing out of the Earth in response to the approach of Cybertron. Unicron is noted by Quintessa to be another name for Earth, and Optimus Prime recognizes Unicron as Cybertron's ancient enemy. Quintessa plans to drain Unicron's energy to restore the damaged Cybertron, killing life on Earth in the process. Simmons later helps Burton locate an ancient book containing details about Unicron, noting that the center-point of Unicron's horns (during the era when all of the Earth's continents formed Pangaea) is Stonehenge. Megatron and Quintessa begin draining energy from Unicron but are foiled, and later Quintessa (disguised as a human) approaches a scientist studying one of Unicron's horns to warn him not to touch the chaos-bringer and offers a way to kill him.
Video games.
Unicron is among the characters appearing in the 2004 "Transformers" video game for the PlayStation 2. Unicron begins attacking Cybertron, requiring the Autobots to collect enough Mini-cons to create a power-up mode for Optimus Prime. The player must chase Unicron as he orbits around Cybertron and enters his maw as he prepares to fire, blasting him with the Matrix Cannon until eventually Unicron is destroyed.
Unicron is mentioned a number of times in "". Eons ago, Unicron created Thunderwing to serve him and destroy the Matrix of Leadership. After Unicron's demise, a meteor of Dark Energon with Thunderwing sealed within crashes on Earth. Optimus Prime comes across the meteor and finds Thunderwing who reveals that he is a minion of Unicron and his mission was to destroy the Matrix. Thunderwing seeks help from the Decepticons for the repairs needed. He fails thanks to the combined efforts of Prime and Jack Darby and falls into a volcano.