Thrull

Thrull was the planet that Galvatron ended up on after being thrown out of Unicrons body. It orbits the red giant star, Hydran.

Spending such a long time buried in one of Thrull's Plasma Pools severly damaged Galvatron's mind, driving him stark-raving mad.

After violently attacking his own troops for attempting to steal him away from his "kingdom", Galvatron left Thrull, but not before he could destroy the planet for no reason at all while cackling wildly.

Galvatron's pretty crazy.

Dreamwave produced a poster of Megatron emerging from his lava bath where the planet was mispeleld 'Thrall'. Crazy Canadians.

From Teletraan I: The Transformers Wiki, a Wikia wiki.