Myu

The Myu (ミュー, Myuu) is the name of a peculiar creature that uses spikes on its upper side to defend itself and impale enemy and prey. The underside of a Myu has never been seen before, so it is hard to determine what exact species it is, although from its size, it is most likely insectile. Link found these in Zelda II: The Adventure of Link and used the Downthrust technique to easily kill the beast.