The Egg Scrap Mech is a large mechanical amalgamation of scrap metal. The Egg Mobile is attached to the Scrap Mech's head. Its right arm is the head of a tunnel boring machine while its left arm is the digging wheel from a bucket wheel excavator. The Egg Scrap Mech also has four long spider-like legs made of excavator scoops on the ends of steel beams that it uses to climb walls.
Inside a large oil drum, Eggman uses an electromagnet to assemble a huge mech out of scrap metal. The fight begins with the mech climbing the inside of the oil drum with crates falling onto Sonic and Tails. Each falling crate's proximity is indicated by an arrow pointing downwards, which changes color as the crate approaches closer. Some of the crates contain spikes which pop out at certain intervals and some explode after a countdown. After receiving enough hits, the mech climbs out of the drum and Sonic and Tails must follow it with the Copter Combo. Afterwards, the mech will jump around the background a few times before finally jumping onto the ground in an attempt to stomp Sonic and Tails. The player must dodge and quickly use the Rolling Combo to hit its feet before hitting Eggman's cockpit one last time.
The way the crates fall in this boss fight is similar to various puzzle games.
If the crates fall onto Tails, he will die, although this does not happen with Sonic (as long as he has Rings).