Mosqui
From Sonic Retro
Mosqui (モスキー / Masukī) is notable as being one of the few badniks who has appeared in more than one game. They can be found in both Sonic CD and Knuckles' Chaotix. It is based on the mosquito.
This little rascal of a badnik attempts to fly down at high speeds and puncture you. They are very easily dodged, and can be destroyed in the air or when they're stuck in the ground. When broken down due to age, their flight speed and reaction time are slower, significantly reducing any threat they pose. In Sonic CD, if you go off the screen, they don't come back, even if you didn't destroy them (unlike all other undestroyed badniks), so be quick if you want those hundred points!
Sonic CD PC Manual Description
The Robot Mosquito flies slowly through the air. When it sees an enemy it swoops to attack!