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Wikisimpsons - The Simpsons Wiki
Radioactive Man Icon.png The contents of this article or section are related to the Radioactive Man universe. They are considered fictional in The Simpsons.
Animal Information
Species: Dinosaur
Color: Green
Gray hair
Male ♂
Relatives: Dr. Crab
First Appearance: Radioactive Man, Man of Radioactivity

The Grumpisaurus is one of the dinosaurs that Dr. Crab created.


Dr. Crab stole the Foreverlution Formula from Dr. Claude Kane II which he used to bring dinosaurs mixed with human DNA from his relatives to life. The Grumpisaurus was one of these dinosaurs. Grumpisaurus stepped on Radioactive Man, then complained when Radioactive Man called him an "old fossil". The Grumpisaurus then ranted at Radioactive Man about how his species should still be the dominant species if it wasn't for the comet and the ice age. He then turned around to look for food and hit Radioactive Man with his tail as he did so.

When Dr. Crab's base was destroyed the island sunk into the ocean, leaving the dinosaurs in the water.