Billy Fitzgibbons is a minor antagonist in The Secret of NIMH. He is the son of Farmer Paul Fitzgibbons and his wife, Beth. He is shown when he catches a naked Mrs. Brisby in a basket and tells his mother not to let Dragon in yet. He asks his mother for permission to keep her, but the former refuses and tells him to put "it" outside. He asks again, promising to keep her in Porky's old cage. So, it was done. Joshua Lawerence did his voice.