Primitive Star is Patrick's prehistoric ancestor seen in the episode, "SB-129," who is a primitive starfish, as his name suggests.
Primitive Star has a large slopping forehead and a large ape-like mouth with a notable underbite, his gums are blue and his teeth are very large and thick and a pair of white sharp tusks are pointing out of his mouth. He wears a loin cloth that can be replaced upon tearing. Like Patrick and Patar, he has five points and is pink, but looks quite different from both stars.
Primitive Star was not very smart. He could not talk as Bikini Bottom citizens of today, but instead communicated with growls and whimpers. His high tolerance for pain is what kept him holding onto the angry jellyfish and repeatedly getting stung. He is not to be confused with Patar, a slightly more intelligent star.
He had no common sense and lived 546 million years ago during the Pre-Cambrian period. He was revealed when Squidward attempted to find a quiet place to play his clarinet, Clary. At first, the meeting between the two was awkward yet calm, he even licked Squidward's arm out of curiosity.
When a Jellyfish swam by, he became afraid and ran away screaming with Primitive Sponge. He is later seen holding a jellyfish and being continuously stung by it, screaming and passing it to Primitive Sponge. Squidward became annoyed at their screams and told them they were supposed to catch the jelly, not torture themselves with it. Taking a stick and loin cloth from both primitives, Squidward crafted two Jellyfish Nets and showed them how it worked, both primitives took the nets and ran after the jellyfish while Squidward went back to his clarinet playing. This, however, would prove to be a bad decision, as neither found the sound very pleasant and angrily pounded their chest and chased Squidward back to the time machine.