The primitive tapeworm only appears in the episode "SB-129," swimming beside Squidward. As the worm swims by Squidward, Squidward brushes himself off and replies, "Whoa! I guess this is before manners were invented!"
The worm has light green skin, but there is some burnt yellow mixed in. It has green eyes, and burnt yellow patterns on its slender, flat body. It also has a small, dark green line on its back.