Egg Gravity is a upgraded Egg Mobile that has gray and red spheres you can walk on, just like in the Egg Snake boss battle. The Egg Mobile is mostly blue with two gray lines on each side. G-merl is located on the bottom of Egg Gravity.
This battle takes place on an elastic "bridge" with the Egg Gravity (which Eggman is sitting in) connected to it. Spikes are on both the floor and the ceiling and the Egg Gravity itself is protected by electricity. The only weak point this time is G-merl. At both sides of the arena, there are chutes that will take the player to the opposite of the bridge, thereby allowing the player to attack G-merl, as Eggman will flip occasionally. When the player attack him, Eggman is launched up (or down) into the spikes and damaged. After every hit, he will spin wildly, going back and forth in an attempt to hit the player. The more hits taken, the faster he will move. Eggman also "leaps", causing the player to slingshot into the spikes above and below the arena. This also holds true when the player hits G-merl, as Eggman's momentum will launch them into the spikes if they do not get away quick enough.
After the player defeats this boss with eight hits (six on Easy mode), the player will be sent to Altar Emerald, which will be unlocked in Chaos Angel's Zone Map.