Bristleback

Bristleback hates being a Pretender. He was forced into undergoing the process when he discovered, to his great dismay, that his steel skin was somehow inferior to other Transformers', corroding and rusting upon contact with Earth's atmosphere. Worse yet, his bulky and cumbersome Pretender shell has transformed him from a once-quick-footed fighter to one of the slowest movers in the Decepticon ranks. A ceaselessly foul-mouthed, bullying malcontent before these indignities, Bristleback has only become meaner since. His Pretender shell's one redeeming feature is the spikes on its back, which secrete a powerful corrosive acid upon contact. Bristleback dreams of being assigned to space missions, where his rust condition will no longer be an issue.

He can combine with his fellow Pretender Monsters to form Monstructor, curiously without any rust problems of note.

Team : Decepticons