Drill Eggman
From Sonic Retro
Drill Eggman is the first boss in Sonic the Hedgehog 2. Robotnik attacks Sonic and/or Tails while in a small buggy. A drill is attached to the front that will cause damage, regardless of if Sonic or Tails is spinning. Players must jump on the cockpit eight times to defeat him, while he drives left and right across the field. 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.
Sonic Cafe
File:Sonic2-cafe-image22.gif
More armor this time.
The Sonic Cafe mobile phone re-release of the game features this boss with slightly more armor.