The Aero Egg (エアロエッグ,Earo Eggu?) is the fourth boss of Sonic Advance 2, that the player fights at the boss act of Ice Paradise. The player has to destroy by bounce to the plate on its tail and hit eight hits to the cockpit to destroy this flying vehicle.
Aero Egg is based on what appears to be a robotic snake. The Egg Mobile on the top is the head while the tail is a small platform you have to get on to defeat this boss. It is mostly blue and gray with some orange. It has three spiked-balls that attach the Egg Mobile and the tail together.
This robot flies in the air and drops bombs to harm the player. To defeat it, the player must wait for the end of the tail to move horizontally. Then the player has to jump over the missiles, that Eggman starts dropping from the mobile and jump onto the end of the tail. The end of the tail, once jumped on, will make the player bounce off of it, and the tail will move vertically. The player then has to move towards Dr. Eggman and hit him. The player has to do it eight times. Its tail can't be jumped on when it's vertical, so the player has to wait for it to turn horizontal in order to jump onto it, but it won't stay horizontal for long. However after four hits and during the pinch mode, Eggman will start dropping missiles at a faster rate to make the boss more challenging. After another four hits, the vehicle gets destroyed and crashes to the land.
The Aero Egg later returns in XX. The pattern is faster as it was in pinch mode and it only requires four hits in order to destroy it again.