Pointdexter
From Sonic Retro
Pointdexter, or Puff (パフ) in Japan, is a pufferfish badnik from Sonic the Hedgehog 3 that swims around in the waters of Hydrocity Zone. Its name is a play on the word "poindexter". These badniks periodically inflate their spiky bodies. Needless to say, don't try to attack while their defenses are up. There is a badnik with similar behaviour in Sonic Advance, called Senbon.