The Spring Stadium Zone boss is a modified Egg Mobile with arms to catch or smash its target.
Inside the arena with many retracting spike panels, Robotnik's Egg Mobile will lower down with a new contraption, one with lanky arms and hands with spikes on the end. He will move around pounding the floor vigorously, then eventually stop and repeat. While pounding, he lowers his Egg Mobile, thus giving Sonic an opportunity to attack. It is best to get behind him to attack rather than from the front or sides. Alternatively, the player can lure him to an area that contains springs, jump up to a platform, and attack him from there. Only direct hits on the glass cockpit will damage the Egg Mobile; anywhere else will harm Sonic. If Robotnik is hit during either of his two phases, he will immediately switch to the other. After every hit, the Egg Mobile will slightly increase mobility speed. After eight hits, the Egg Mobile gets trashed, and Robotnik flees the scene.
- Once Robotnik is defeated, the retractable spikes on the floor no longer work.