Dexter's Laboratory Wiki
Caveman - Old Flame
Aliases Primal Genius,
Mr. Caveman,
World's First Genius
Gender Male
Species Neanderthal
Family His tribe
Interests Helping his tribe, jumprope, fire
First Appearance Old Flame
Voiced By Frank Welker

The unnamed caveman (also referred to as Primal Genius or simply Mr. Caveman) is a minor character in Dexter's Laboratory. He only appeared in the episode "Old Flame".



Eons ago, the Caveman was a simple hunter and gatherer in his tribe who one day found himself cornered in a cave by a vicious prehistoric bear. However fate would smile on the seemingly doomed Caveman when a lightning bolt stuck a nearby tree, causing its flaming branch to fall near the cave and scare away the bear which amazed the Caveman. Initially intimidated by the flame's pain and glow, the Caveman realized it could provide warmth and be controlled. With his new discovery in hand, he ran off back to his tribe to show them the wonders of fire.

Old Flame[]

Just as he arrived at his tribe's cave, a time traveling Dexter suddenly appeared, having used his time machine to travel back in time in order to meet the world's first Primal Genius and take him to the future so he could witness how his little discovery helped to advance the world. Upon taking him through time, Dexter took the Caveman on a tour through his laboratory to show him all of his inventions, however Dexter failed to realize that the intimidating and unfamiliar visage of his inventions would terrify the Caveman, and he then fled in terror from the monstrous machines. A worried Dexter then sent out his Recon Probe Droids to find and secure the Caveman, but he easily dispatched them and even tried to eat them believing them to be birds.

The Caveman then grew hostile towards Dexter, but before he could attack Dee Dee appeared and was shown to be capable of communicating with the Caveman who was pleased to meet her, with Dexter suspecting that Dee Dee's own primitive behavior allowed them to communicate. Dexter then had Dee Dee "translate" throughout his tour, but Dee Dee and the Caveman grew bored and ran off to play games and make chalk drawings in the lab while Dexter continued his tour oblivious of their departure. When Dexter finally realized they were gone, he found them playing jumprope in the lab and grew furious with Dee Dee for "contaminating" the Caveman with her childish games. Dexter then quickly sent the Primal Genius back in time before anymore damage could be done to his psyche.

By the time the Caveman returned to his own time though, he quickly extinguished the fire he had discovered and revealed he had taken the jumprope back with him which he then shared with the rest of his tribe who began to play the childish games. How this affected the course of history or whether Dexter corrected this temporal hiccup is uncertain.


The Caveman is a primitive human who simply wants to be left alone, protect his tribe and provide for them. He is easily intimidated and prone to anger, but he is really kind at heart as shown when he happily shared his discovery with his family, his quick friendship with Dee Dee and his appreciation for games and art. He is a skilled hunter, although he will avoid attacking prey unless armed. He is also a very skilled and creative artist as seen with his chalk drawings, although he seemed to think chalk was edible.



Adult Swim Primal Dexter's Laboratory Bumper

  • The Caveman appears to be based on the character Ugh from the Hanna-Barbera cartoon Dino Boy, one of many references to HB present throughout the series.
  • He is almost completely identical to the caveman Spear, one of the main protagonists from Genndy Tartaovsky's later cartoon, Primal, the only difference being his height, forearm size, and loincloth color.
    • The similarity was further noted in an Adult Swim bumper showcasing Spear being transported to Dexter's Lab and acting out the same role as the Caveman.