Episode Title:Joshua & Margaret Investigations.Episode Description:During Jake's birthday party, Jake tells Finn and BMO a story about how his parents Joshua (voiced by Kent Osborne) and Margaret (voiced by Maria Bamford) hunted down a dangerous menace in the woods of Ooo before Jake was born. It is revealed that while hunting some sort of monster, Joshua was bitten by an otherworldly shape-shifter. Eventually, the wound started to grow, resulting in Jake being born from his father's head.