Egg Scrap Mech

Egg Scrap Mech is the boss of Oil Desert Zone in Sonic the Hedgehog 4: Episode 2.

Inside a large oil drum, Eggman uses an electromagnet to assemble a huge mech out of scrap metal. The fight begins with the mech climing the inside of the oil drum with crates falling on Sonic, Tetris-style. Some of the crates contain spikes and some explode after a countdown. After receiving enough hits, the mech climbs out of the drum and Sonic and Tails must use the Rolling Combo to hit its feet before hitting Eggman's cockpit one last time.