In Simon Petrikov, it's shown that even years after his defeat, GOLB/Betty hasn't been forgotten by Simon, who now suffers an existential crisis over being the last 20th century human in the Land of Ooo and missing Betty, even having a shrine dedicated to GOLB/Betty in his zoo-like room. He even tries to conjure a spell to bring Betty back using Choose Goose (who'd turned evil) as a sacrificial pawn, but it fails and instead opens a portal in his head twice that transports Fionna Campbell's pet cat Cake, and later Fiona herself in Cake the Cat, from their universe into Simon's.