Following the recent announcements regarding Marceline and Princess Bubblegum, I decided to make a very special post to commemorate: an OSR monster entry for Marceline! The stats are compatible with Labyrinth Lord, AD&D and similars; and those in brackets are in ascendent values, compatible with Lamentations of the Flame Princess, Old Dragon and similars.
Marceline, the Vampire Queen of Ooo
HD: 13, or 66 hps, 106 in battle form
At: 11 [+9] , Battle Form 8 [+12]
Damage: 1 Bite 1d4; Battle Form 2 claws 2d6 e 1 bite 3d4.
AC: 0 , Battle Form -2 
AL: Chaotic Neutral
AL: Chaotic Neutral
. Abominable Presence: Marceline is capable of changing her features to induce fear. All creatures with 4 HD or less are instantly paralysed. The others may make a saving throw or else be paralysed for 2d4 turns.
. Transformations: Marceline may shapeshift to innumerable different forms, normally with traces of bats, wolves and undead monsters. The GM must decide the capability of each new form she adopts - but, in general, she can take a Battle Form which have her size go from Medium to Huge, gain +40 hit points, +3 to Attak, +2 to AC and make 2 claw and 1 bite attack per turn.
. Resistances: Marceline has many untold resistances and defenses. One that is stated at the cartoon is her almost fire immunity (reduce all fire damage she receives by 100 points). As a Vampire, she must also have some immunities to enchantments and death spells. The GM is free to giver her specific resistances.
. Magical Instruments: Marceline owns a variety of different instruments whose special abilities are yet to be discovered. Many are able to play without an electric amplifier and it is known that her Axe Bass was used by her father as a weapon. The Ax Bass is, at least, a bass that can be used as a battle axe +3 that deals 2d10 damage per strike. The GM is free to give all her instruments new powers.
. Another Powers: With each episode, Marceline's power list grows. She is able to fly at will and with perfection. She has control over each and every strand of her gigantic flowing hair. She is able to drink the shades of red from people and objects (and, actually, that is what she needs to feed upon). She may also turn invisible wherever and however she wants - although that might not work in battle, by GM discretion. Anyway, the GM is free to create new power for the Vampire Queen.
. Weaknesses: Being a vampire, sunlight causes great damage to her. Every turn under sunlight, marceline loses 10% of her maximum HP undil destroyed at 0 hp. However, wearing long sleeved clothing and big (cowboy) hats are able to avert this nasty effect. But, worst than her weaknesses to the sun, Marceline is helpless against Ghosts. All her power won't work on them and she cannot hurt or defend against them. In fact, someone in Astral Form is capable to physically hurt Marceline, hiting her automatically and dealing 10 times the damage (so, 1d4 dagger would deal 10-40 damage to her).
Well, I hope you guys liked it. Marceline is my favorite character from Adventure Time, and I intend on speaking more about that series in the future (who knows, maybe even adapting it for OSR?).