Egg Spider
From Sonic Retro
The Egg Spider is the fourth boss in Sonic Advance, which takes place in Ice Mountain Zone. This fight is underwater, making this fight harder than the usual. Eggman will move around left and right, making a stop to make ice blocks fall; jump on the ice blocks to reach eggman (a total of eight hits to destroy him) or to take air. When the boss is defeated the water level will decrease.