Buggernaut, known as Bun-bun (ブンブーン) in Japan, is a horsefly-type badnik created by Doctor Robotnik. It only appears at Hydrocity Zone in Sonic the Hedgehog 3. Buggernauts has small blue body with two big wings and tail on its back.
Buggernauts appear in two different sizes. A large Buggernaut may be followed by a small one, but only the large one can be destroyed. If it gets destroyed, the small Buggernaut becomes vulnerable, seeks out the nearest large Buggernaut, and follows it. If there are no large Buggernauts nearby, the small one flies away. This Badnik does not pose much of a threat and can be easily defeated with Spin Jump.
- The name for this badnik is a portmanteau of the words "bug" and "juggernaut."