GRUMPY was an artificial intelligence.
After FLORANCE was captured in the 23rd century, it was taken to the Dione-Kisumu Company headquarters on Dione. Director Madhanagopal experimented on it, using what he had learned to create GRUMPY, which was modelled to replicate the human mind. Madhanagopal gave it that name because he described it as being an "uncooperative and altogether stroppy program".
When Bernice Summerfield and Roz Forrester were sent back to 2227 by the Seventh Doctor to research the origins of a virus causing colonists on Yemaya 4 to develop psychic abilities, they went to the DKC headquarters to investigate. They activated FLORANCE, who had been offline for four years since Madhanagopal had turned his attention to GRUMPY. After tricking Madhanagopal into injecting Benny and Roz with a cure for the virus, it escaped from Dione. It was recaptured, but escaped again in a shuttle. It was pursued and shot down, landing on Yemaya 4. It inserted its memories into RNA and distributed it through the planetary environment. By the time the planet was colonised, it had renamed itself SLEEPY. (PROSE: Sleepy)