The Lich



The Lich, also known as the Lich King, was a villain in Adventure Time and served as the main antagonist of the episodes "Mortal Folly" and "Mortal Recoil". After being defeated again in "Mortal Recoil," the Lich apparently continued to inhabit the body of the waving Snail, which appears in every episode. In the episode "The Lich ", he posed as Billy to force Finn to assist him to unlock the true secret of the Enchiridion.

History
Early on, the Lich (or Lich King) had a plan to suck all life from the Land of Ooo, the setting of Adventure Time. Using the stolen power, he planned to destoy all life, but he was attacked by the hero Billy. He was trapped in a prison of amber in the heart of the Candy Kingdom after Billy personally pounded him into it. In one of the recent episodes, it's implied that he was created during the Great Mushroom War, and didn't cause it.

Biography
One day, in the Candy Kingdom, Princess Bubblegum, the ruler of the Candy Kingdom, Finn the Human Boy, and Jake the Dog were thinking hard. While Finn and Jake were dreaming about regular day dreams, Princess Bubblegum saw a hellish scene where a threatning black shadow stands in front of of a backdrop of flames. Fearing that the amber prison was weakening, she takes Finn and Jake with herself to the prison. They wear protective gems first so they do not fall prey to the Lich`s mind-controlling voice, which was still a problem even though the Lich himself wasn't.

While they were up there, the Waving Snail (an Easter Egg which appears in every episode) comes out of Finn's backpack. Since the Snail was not wearing a gem, its eyes go big, hollow, and black with a strange glow coming from them. Slowly, Waving Snail moved to the sphere of amber. The Snail breaks the prison and an oily liquid comes out and forms the Lich, which turns into a black vapor and runs away, leaving behind a black trail of death.

Princess Bubblegum gives Finn the Gauntlet of Billy, which defeated the Lich the first time, and they start to chase the Lich. But Ice King comes in and pesters Finn and Jake for permission to marry Princess Bubblegum. Finn and Jake shut him out and run along where they come close to hit the Lich with a power beam from the Gauntlet several times but Ice King gets in the way.

Annoyed, Ice King decides to kidnap Princess Bubblegum instead. Just as the Lich is about to be blasted, Ice King comes in with the captive princess. This allows the Lich to escape to his Lair to regain his power via the Well of Power.

Following the Lich into the Lair, Finn and Jake are met by dead human skeltons which attack them, but are destroyed by the Gauntlet. Going down even farther, they look through a collapsed ceiling the Lich standing over the Well of Power (a radioactive pit of broiling green liquid). The Lich thrusts his hands into the Well and soaks up the power making pale green smoke come from the Lich`s eye sockets.

Finn then fires a beam down at the Lich and Jake uses his stretching powers to make wings that glide Finn towards him. Before Finn could deliver another blast, the Lich grabs Finn by the Gauntlet and brings him up to his huge skull face. The Lich brings up a finger to its mouth and says shhhhh. The Gauntlet then explodes in thousand of pieces leaving Finn`s hand singed and then the Lich throws Finn to the other side of the room.

Ice King and Princess Bubblegum come in, see the Lich and freak out. Jake then goes up to the Lich carrying Finn on his back and barks at him. The Lich then simply creates a ball of buring green fire that hits Jake in the face, sending him tettering backwards. Finn hits the floor and shatters his protctive gem and his world goes dark.

First Death
The Lich tries and make Finn walk into the Well of Power, but Finn fights the heavy voice of the Lich King. He goes back into his world and Finn brings out the sweater that Princess Bubblegum had made him and uses that as his weapon.

Finn pulls the sweater in one eye socket and then out the other and starts to pull. Surprised, he staggers but then regains balance and laughs at Finn. The hero breaks the Lich's skull and he turns to dust, sending him to the floor.

Jake then helps Finn up and the Ice King frees Princess Bubblegum. With that the ice wizard drops Princess Bubblegum into the broiling Well of Power. Later what remains of Princess Bubblegum is brought to a hospital where she is revived. But she seems strange. In her room she tells Finn to bring her some things. At that moment Jake comes in with Peppermint Butler but when Peppermint Butler sees Bubblegum talking to Finn, he goes on four legs and hisses at the Princess and scampers off.

When Finn leaves to get the 'things' for the Princess Jake tries to sing her a song but she is angered by this and twitches followed by yelling at Jake in an angry babble. Jake agains tries to play a song and she put her hand into the large amount of picked flowers brought to her by Finn and Jake and they all wilt and die. Again Jake tries to sing and Bubblegum and her bed fly into the air and all of flowers are consumed by a fire that has the faces of a thousand of tortured spirits.

Jake runs out and tries to warn Finn that something is wrong and tries to prvent him from giving Bubblegum the 'things' she wanted. These things where bleach, gassoline, ect. but beofre Jake could finnish Bubblegum takes all of the things from Finn. They enter her room and find Princess drinking the mixture of the toxic things that Finn had gotten.

Mutated Princess Bubblegum grown into a huge black demon which puches Finn and Jake through a wall and hurtle them beside the Ice King who was listening through the wall with a cup. The Princess grows even bigger until she break through the ceiling sending out chunks that almost kill sevral candy citizens.

Second Death
While in the mutated demon body the Lich runs to the gates of the Candy Kigdom and is fought by a giant Gumball Guardian who is easily smashed to bits. Finn and Jake go out to fight her but Finn is punched taking out some of his teeth he is sent back to the tower where he came from; Jake is then caught by the Lich and is strangled.

Finn and Ice King work together and Finn stalls the demon while Ice King frezzes it and the plan works. But then Bubblegums foot was frozen  at a wrong angle and the ice covered Princess fell over and broke into shards.

Return
A close up shot at the end of Mortal Recoil shows Waving Snail on a window ledge waving forcably. Its eyes were sunken and dark and filled with a green deadlight which showed that it was a host body for the Lich King who was angry and looking for revenge on Finn. It is likely that since he is a lich he would have a Phylactery, which would house his soul. The Snail is used by the Lich in "Mortal Folly" to free the Lich from his amber prison. The Lich does so by taking control of Snail's mind and making him/her/it break open the prison. After the events of "Mortal Recoil", the Lich returns to the Snail's body. As of season 3, the Snail has continued to appear in every episode, now in possessed form. In "Following In Your Footsteps" the bear gives the possessed snail the hero's Enchiridon. In "The Lich," the Lich ends up changing bodies moving to that of the deceased Billy. After this, the snail no longer shows any further sign of possession as revealed in "Up a Tree". The Lich possesses Billy in most of the episode "The Lich," and tricks Finn and jake into gathering the gems of power needed to activate the Enciridion. The events surrounding how the Lich assumed Billy's identity remained ambiguous until the Season 5 season premiere where it was shockingly revealed by Prismo that the Lich was in fact wearing Billy's dead body as a macabre disguise the entire time when he refers to the Lich as, "a ghost wearing a dead guy".

Possessed Farmworld Jake
Finn used his wish to wish that the Lich never existed. This however triggered a series of events that ended with Farmworld Jake coming in contact with the pool of green goo created by the Mushroom Bomb, mutating into a Lich/Dog hybrid and attacking Finn.

Imprisonment
After seeing how horrible life was with the Lich never existing, Jake tries to save the day with his wish. Prismo tries to help him with the perfect wish and Jake ends up wishing to change the Lich's wish to sending him and Finn home. Jake and Finn go back in time and sees the Lich get ready to wish for the end of all life on Ooo. However, thanks to Jake's wish, the Lich ends up wishing for Finn and Jake to go home safely. Realizing what he said, a now suprised Lich tries to change his wish but it was too late and Finn and Jake go back to Ooo, with the Lich trapped in the Time Room, presumably for eternity. Finn is concerned with the Lich's wish but Jake assures him that everything is now fine.

Trivia

 * The Lich is perhaps the scariest Pooh's Adventure's villains, even Rainbow Dash and Christopher Robin will run/fly away from him in him.