His name is Legion, a new species of Transformers created when the Unicron-enhanced cells of the Decepticon leader Galvatron were spread throughout Earth's atmosphere in the year 2005. Fusing with various creatures and vehicles and wearing the face of Megatron, the vicious Legion army has converged on the city of Tokyo, the site of Galvatron's catastrophic impact.
They appear to have fluid-filled organic components and enjoy the taste of sweet, sweet Kiss Player flesh. They're kind of horrible.
Following a presumably Legion-related subway attack in Japan, a lone Legion member came upon a bleakly despairing Atari Hitotonari and offered to end her suffering by killing her. Cornering the panicked girl, it was about to make good on its offer when the Ne-04 Autrooper interfered. When the Autrooper disgorged the unconscious Kiss Player Shao-Shao Li, Atari merged with it and quickly beheaded the Legion, seemingly terminating it.
Shao later awoke to find herself a prisoner in one of several tubes containing very alive and hungry Legion heads in the basement of Earth Defense Command headquarters. It appears that the E.D.C. has been conducting human experimentation on captured Legion units for an unknown purpose.
Another Legion that attacked Marissa Faireborn at sea was described by Optimus Prime as a ParasiTech fusion between an octopus and a shipwreck. As ParasiTech fusions are also used by the Autroopers of the Earth Defense Command, it may be that there is a connection between the two. A SINISTER one.
Less than six months after joining the E.D.C., Atari ate an omelette (which she had prepared) that contained a miniaturized Legion. The surprisingly communicative and wacky intestinal invader was engaged and defeated by Atari's shrunken Autrooper and dissolved in the girl's digestive acids. There was, astoundingly, nothing psychosexual about the encounter beyond this.
A group of 23 Legions attacked the recently reconstructed Tokyo Bay Bridge, but were defeated by the combined efforts of Hot Rod and Shao-Shao, though not before repeatedly attempting to molest Shao with their tentacles.