Walkman

The Walkman is an audio-recording device that Finn uses twice in "It Came from the Nightosphere." It uses cassettes to record and play back music, typical of recreational 1980s music-recording equipment.

Uses
In "It Came from the Nightosphere," Marceline asks Finn to beatbox for her so she can perform a song on the Axe-Bass, to be recorded by the Walkman. The song, about her father and how he ate her fries, saddens Finn so deeply he cannot continue to beatbox. Because of her apparent falling out with her father, Finn decides to summon him; however, her father, an evil vampire, begins sucking up all the souls in Ooo.

In order to distract him, Finn plays the Fry Song for Marceline's father, allowing Finn the opportunity to free the souls of Ooo from the vampire's body.