Mono Beetle is a robot created by the military organization G.U.N., and part of the Beetle series of robots. It appears as an enemy in Sonic Adventure 2, Sonic Adventure 2: Battle, Shadow the Hedgehog and Sonic Generations.
Mono Beetle only floats around and has no method of attack, unlike other robots in the Beetle series. They can occasionally be used as platforms for characters to Homing Attack across. Some versions of Mono Beetle have security cameras. When one spies you, it will bob up and down excitedly.