Egg Hammer Tank
From Sonic Retro
Egg Hammer Tank is the first boss in Sonic Advance, which takes place in Neo Green Hill Zone. Dr. Eggman appears on his Eggpod and flies away, then, Egg Hammer Tank appears. It's a tank with a giant hammer attached. Basically, the player must hit the cockpit eight times (or six if in easy mode) to defeat him, while he drives left and right across the bridge. At the seventh hit (or fifth if in easy mode), he will use the hammer to make the vehicle jump.