Abraham Lincoln

Abraham Lincoln debuts in the Animated Short, where he encourages Finn to believe in himself after warping his brain in the past and to Mars. He is also seen in "Business Time," where he is a character included in a game on BMO.

He is referenced in "Crystals Have Power." Jake states, "If I had a penny for every time someone went crazy hopped up on magic energy... I'd be Abe Lincoln!"

He is referenced in Issue 3 of the Adventure Time comic. When Finn is telling everyone how to beat The Lich, he says that just like Abraham Lincoln said in the past and on Mars, you need to believe in yourself.

The first time he ever appeared in the official series is in one of the many pictures in Hunson Abadeer's house. He is a major character in the episode "Sons of Mars," and is the King of Mars. He lost his immortality (and seemingly his life) in the episode in order to save Jake after he was accidentally sent to the 37th Dead World and changes into the statue from the Lincoln Memorial.

Appearance
Abraham Lincoln looks pretty much exactly like the real-life Abraham Lincoln. He wears a full tan-brown suit with a dark red bow tie. Two major differences from his real-life appearance are that, in the show, he floats like Marceline, and he has a yellow light surrounding his head. He also doesn't wear his stovepipe hat. Unlike most characters, his hands have five fingers. He sits atop a throne that is engraved with the symbol ♂, the astrological symbol of mars, which has come to also represent "male" in contemporary popular culture. This symbol can also be found in the arena in which Abe Lincoln sits.

Quotes
"Pen, your mind has been transported back in time, and to Mars." "It doesn't matter. What does matter is you need to believe in yourself!" "Magic Man, it bums me out to see this. I remember when you were really cool..what happened Magic? Why did you go crazy?" "If you had just learned to care about living things again you could have come whenever you wanted (oh Magic Man, you sad Magic Man) instead you bummed around Ooo acting like a jerk for 200 years apparently." "Magic Man I give you two choices: one is total annihilation. The wand will touch you and your soul will meet with deat; the second is to use the power of the wand to convert your body to stardust where your consciousness will be jettisoned in the infinite cosmos on an endless journey of wonder and discovery." "My judgement was less than the standard by which I judge my peers..of which I have none."

Trivia

 * Pendleton Ward stated on his Formspring that Abraham Lincoln might appear in Season 2. Beyond a brief mention, this did not come to pass.
 * As stated by Rebecca Sugar, Abraham Lincoln is the equivalent of Jesus in Ooo. However, according to Adam Muto, he is more of a "recognizable figure," while adding that it would be "a stretch to call him a religious figure."
 * He has a very detailed face, unlike most Adventure Time characters.
 * It is implied that Abraham Lincoln has bargained for a soul with Death in the past, using a penny as barter, similiary to how the dead ones were transported through a river in Hades.