Sir Purssefus or Purrsy (Frank Welker) for short, is Betty's mother's spoiled, surly, beloved Siamese cat. She lavishes him with attention and treats him like he’s Betty’s younger sibling. And just like any other spoiled rotten little brat, Purrsy is petty, jealous and conniving. Purrsy has accidentally accompanied Betty on one of her missions, but being a cat has not said anything about it. He tends to cause trouble, but the trouble often backfires on him. He also seems to enjoy the company of Maximus I.Q.. Maximus in turn quickly grew fond of him upon first meeting him.