Arthur Brooks is the former secondary antagonist of Big Daddy. He is Julian "Frankenstein" McGrath's social worker. When he finds out that Sonny Koufax is posing as Kevin Gerrity to adopt Julian, he threatens to have Sonny arrested, as this results in the eventual court case. The judge grants custody to Kevin to the dismay of Julian, who wants Sonny as his father. Sonny tells Julian that it can't happen because his real father is present, but they can be friends.