From Sonic Retro
Moto Bug, called Motora (モトラ) in the Japanese manual, is a Sonic the Hedgehog badnik found in Green Hill Zone. It is an overgrown metal beetle only capable of moving forward. They have a fair bit of speed, but are easy to outmaneuver and take out with a simple spin attack. They do not attack back.
Moto Bug would not return to Sonic games until the year 2010. On January 27th, 2010, SEGA America Blogs revealed concept artwork of a redesigned Moto Bug to be used in Sonic the Hedgehog 4. The same Motobug found in Sonic the Hedgehog 4 is also available as a promotional Xbox 360 avatar prop. Another redesigned Motobug appears in Sonic Colours and Sonic Generations.