Fionna

Fionna (previously spelled Fiona, and also known as Fionna the Human Girl) is a gender-swapped version of Finn and created by the Ice King in his fan fiction. She was created by series character designer Natasha Allegri in a series of web comics and drawings. She and the other gender-swapped characters appeared in the season three episode "Fionna and Cake." She is usually seen in the company of her own stretchy companion: Cake. Also, Fionna's enemy is the Ice Queen.