The Primitive Sponge has a large sloping forehead and a large ape-like mouth with a notable overbite, his teeth are large and thick. He wears a loin cloth that can be replaced upon tearing. And like SpongeBob and SpongeGar, he is square and yellow, but looks quite different from both sponges.
Role in series
He is revealed when Squidward attempts to find a quiet place to play his clarinet. At first, the meeting between the two is awkward yet calm; he even sniffs and plays with Squidward's arm out of curiosity.
When a jellyfish swims by, he becomes afraid of it and runs away, screaming with Primitive Star. He is later seen holding a jellyfish and being continuously stung by it, screaming and passing it to Primitive Star. Squidward becomes annoyed at their screams and tells them they are supposed to catch the jelly, not torture themselves with it. They do not understand so Squidward takes a stick and loincloth from both primitives, crafts two Loincloth jellyfish nets, and shows them how it works.
Both primitives enjoy the game and take the nets to run after the escaping jellyfish while Squidward goes back to his clarinet playing. This, however, proves to be a bad decision, as neither primitive finds the sound very pleasant and they angrily pound their chest and chase Squidward back to the time machine.
Willingly getting stung by a jellyfish (witnessed by Squidward)
Jellyfishing (caused and created by Squidward)
Destroying sources of annoying/high-pitched sound (case in point, Squidward's clarinet)
The Primitive Sponge is not very smart. He cannot talk like the Bikini Bottom citizens of today. Instead, he communicates by growls and whimpers. His high tolerance for pain is what keeps him holding onto the angry jelly and repeatedly getting stung. He could understand Squidward's demand for his loincloth. He also looks very crazy when noticing Squidward.
He and Primitive Star are briefly seen in the episode "Ugh" as part of the "When Worlds Collide" song.
Unlike SpongeBob and SpongeGar, Primitive Sponge is not known to have any pets.
Unlike SpongeBob, Primitive Sponge has no eyelashes and has two sabertooth tiger teeth instead of two buck-teeth.
Primitive Sponge became a meme in 2014 and became fairly popular in the spring and summer seasons of 2016. Most people who use the meme often confuse him with SpongeBob's other prehistoric ancestor, SpongeGar.