The Transformers S03 E08 Dark Awakening

"More than Meets the Eye!"

On the run from Galvatron, Spike, Daniel and several Autobots enter a mausoleum and find a surprisingly not dead Optimus Prime. This would be cause for great excitement among Autobots. Unfortunately, however, Optimus is really under Quintesson control and is being used in a plan against his friends.