Brutus is a rat who is a minor antagonist in The Secret of NIMH. He is first seen when Mrs. Brisby is at the entrance and he greets her with his battle ax and she asks him if he's Nicodemus but instead he does not answer and just chases her back the way she came being scary and brutal. Brutus actually turned out to be a good guy as he is seen in the sequel helping Timmy and giving him a whistle.