Advanced Prehistoric Era
The Advanced Prehistoric Era was the second oldest era known after the Basic Prehistoric Era in SpongeBob SquarePants. In that time things was more advanced than in Basic Prehistoric Era like language, writing system, houses, clubs, fire (discovered in the episode "Ugh") and pets. Jellyfishing was also introduced by Squidward in this era. The only known inhabitants were SpongeGar, Patar, Squog, Prehistoric Gary, Prehistoric Krabs and some animals (including jellyfish).