Betony "Beth" Burrito Jakson IV (full title: Beth, the Pup Princess) is a character who exists in the future. She is a close friend of Shermy, who made her first and only appearance in the series finale "Come Along With Me".
She and Shermy appear to live in Marceline's now-abandoned house, which is a reference to how Finn and Jake lived in the Tree Fort, which originally belonged to Marceline. She is a descendant of Jake and Lady Rainicorn.