Captain Peanutbutter is a Labrador Retriever and the brother of Mr. Peanutbutter. He appears in two episodes in season three. He has two unnamed sons. In Old Acquaintance, he informs Mr. Peanutbutter that he has a twisted spleen that is successfully removed in It's You.
He is voiced by "Weird Al Yankovic".
He has a great and healthy relationship for his younger brother Mr Peanutbutter, by whom he is older than by five minutes.
Captain Peanutbutter seems to be the more mature in demeanor out of the two brothers. Perhaps a result of being five minutes older than Mr. Peanutbutter. He shows signs of depression at first which turns out to be a result of his twisted spleen. He appears to be much better after having the spleen removed.
He is very accepting and welcoming of his sister-in-law Diane Nguyen and treats her like part of the family.
Captain also seems to be a caring father to his two sons worrying about what will happen to them if he dies as a result of his spleen and asks Mr. Peanutbutter to take care of them if something happens to him.
Captain is an adult dog who wears a plaid lumberjack shirt, brown suspenders with metal buckles, blue jeans, brown lace up work boots, and a blue-grey baseball cap.
His face looks more mature than Mr. Peanutbutter's.
- He has two unnamed sons but their mother is never shown.