The Egg Scrap Mech is the third boss of Sonic the Hedgehog 4: Episode II, fought at the end of Oil Desert Zone.
This boss fight starts with Sonic and Tails landing in a trash heap. Dr. Eggman uses a magnet to collect the various pieces of junk and make a giant robot with them.
The boss attacks with dropping crates onto the battle field. The player(s) must dodge them to survive, and attack Eggman's cockpit with the Copter Combo to reach it. As the boss receives more hits, it will drop different crate types, including spike crates which shoot spikes like a spike trap, and exploding crates which blow up after a set amount of time.
After enough hits, the boss suddenly leaves the trash chute, and Sonic and Tails fly out of the chute in chase. Outside, the boss begins to leap around Sonic and Tails. Every 4 jumps or so, it will jump directly onto the battlefield. The player(s) should make sure when the boss leaps onto your area that it doesn't leap on them, and also make sure the boss is facing them, so they will be able to land the final hit. Do a Rolling Combo into its "toes" to finally bring the boss crashing down.