Drill Eggman
From Sonic Retro
Drill Eggman is the first boss in Sonic the Hedgehog 2. Robotnik attacks with a small buggy with a drill attached. Players must simply jump on the cockpit eight times to defeat him. As a last ditch attack, Robotnik will fire the drill attachment before the boss is defeated.
A similar boss also appears in Sonic Advance's X Zone.