Taga-Taga
From Sonic Retro
Taga-Taga (タガタガ) is a badnik of Sonic CD, found in Tidal Tempest. It is based on the giant water bug, an aquatic insect. They move back and forth underwater and can be destroyed from underneath. Their only attack: shooting their spikes at you when you approach from midair, then swimming away too quickly for you to catch up.
These robots are also seen in Palmtree Panic, though there they merely jump out of waterfalls in the style of Sonic 1's Chopper badnik.