Egg Ball
From Sonic Retro
The Egg Ball is the third boss in Sonic Advance, which takes place in Casino Paradise Zone. This boss consists of an eggpod and a spikeball. These two spherical objects appear from one of 8 pipes and you must avoid the spikeball while hitting the eggpod; a total of eight hits, or six if in easy mode. The speed of the two balls will increase as Robotnik is hit.