One of the Rats of NIMH who became disaffected with the leader, Nicodemus, because he disagreed with Nicodemus's ideas to stop stealing food, water, and electricity from humans, and to become self-sufficient. He, along with 6 of his followers, left the Rats' colony to start their own, where they could steal as much as they'd like. While starting this colony, he and all his followers were electrocuted, however he was the only one who survived. He became a paranoid shell of himself after that.
He had a son named Racso, and died (in Racso and the Rats of NIMH), while helping sabotage the Thorn Valley Dam Project, deciding that while he didn't agree with Nicodemus's ideals, he would help his son in his new life at Thorn Valley.
In the movie, The Secret of NIMH, he did not leave the colony, but was killed by his own accomplice, Sullivan, in the murder of Nicodemus; it is not known if he had a son.