Sweetie is the family dog who appears in book 4 only. Susan impulsively gives the dog a female name, not realizing that it is male; however, he seems happy with his name and is very affectionate toward her. Frank bought Sweetie after he found out what happened to his own dog when he was younger. He causes trouble to the family (except Susan, though she pays him almost no attention), including Frank and Greg. Near the end of book four, he is given to Gramma.