The ever-insane Tarantulas [link]
that combined psychosis, cannibalism, and a shockingly bright mind into one twisted Predacon, Tarantulas schemed against and backstabbed virtually everyone in the cartoon. While karma caught up with him and he died in an explosion, the expanded comics state that Tarantulas actually let that happen as part of a plan. Take what you will of it.
On another note, does anybody know where I can find him online for a good price?