If you're going by sheer number of costumes spotted at last year's San Diego Comic-Con, Fionna and Cake (the gender-swapped versions of Adventure Time's Finn and Jake) are the single most popular characters ever created. If that's the case, then it's good that we're getting some brand new stories about 'em!

Not only is there a comic out from Boom! Studios by Fionna & Cake creator (and Adventure Time artist) Natasha Allegri, but on February 18, the characters return to television in an episode that features Donald Glover as Marshall Lee the Vampire King. Check out a clip featuring both songs andemotions below!

Glover joins Neil Patrick Harris (who returns as Prince Bubblegum), Roz Ryan (Cake the cat) and Madeline Martin (Fionna the human) for "Bad Little Boy," airing on Monday, February 18 at 7:30 PM Eastern, and probably other times in other places. You can do the math, right? Right.