From Muppet Wiki

Porcupines are large rodents with sharp quills on their backs, which are used as a defense against meat-eating animals. They have appeared in a variety of Muppet productions.

Picture	Name	Show	Description
	Kippi Ben Kippod	Rechov Sumsum	A full-body porcupine
	Wendell Porcupine	Emmet Otter's Jug-Band Christmas
		The Muppet Christmas Carol, and Billy Bunny's Animal Songs	A brown porcupine
		Sesame Street	A yellow porcupine with light brown quills and a black nose appears in the sketch "The King Banishes the Letter P"