Dead Worlds are places where individuals go to spend their afterlife upon death. The first mention of a Dead World was in "The New Frontier" by Jake, who says one must transcend into Glob World. In "The Vault", Finn is shown to have been reincarnated multiple times, suggesting that each incarnation of a person is sent to the corresponding Dead World.
1st Dead World
The 1st Dead World seems to be the equivalent to Hell, as Choose Goose claims that it is for the worst of the worst. The realm includes the remains of various souls trapped into a pool of slime, unable to move or leave, while being constantly attacked and tormented by monstrous creatures. Wyatt is among its inhabitants, and before ascending, Maja.
9th Dead World
The 9th Dead World is mentioned in the episode "James Baxter the Horse". When an angry ghost mauls Finn and Jake, Jake thinks about their impending death. He says that, since a lot of dead people will be there, they might become separated. So as a means of identification, Jake tells him to listen for a rhythmic clapping sound he will perform.
27th Dead World
Intorduced in Comic Issue #53, the 27th Dead World is a plane where souls go when they die to wonder aimlessly. Jake goes here to reclaim the stolen youth of Finn and many others, stolen by the Governor of Ghost-O-Rica, who plans to get so much youth that he can come back to life. It is guarded by a red creature with six skulls.
30th Dead World
37th Dead World
The 37th Dead World is a mentioned Dead World. Jake's ghost went to the 37th Dead World when he was killed by the Wand of Disbursement on Mars. Death appears to inhabit this world and Abraham Lincoln was able to visit it at will. The 37th Dead World may be related to the Land of the Dead, as Death is shown to dwell there in "Death in Bloom".
In "Together Again", Finn is assigned to this Dead World, before being reassigned to an unknown Dead World.
45th Dead World
50th Dead World
The 50th Dead World seems to be the equivalent to heaven as it's proclaimed to be one of the highest of Dead Worlds. It was first mentioned in "Ghost Princess" when Ghost Princess beckons her love, Clarence, to ascend with her there. This Dead World is mentioned again in the episode "The Suitor" by Braco, who stated that he wanted to float up to it with Princess Bubblegum.
This Dead World is finally seen in "Together Again", wherein it is revealed that the way to get there is to be free from all desires, even the desire to enter the Dead World. Jake’s soul is sent here after his death.
Unknown Dead Worlds
|"Low Level Dead World"
(as referred to by Jake)
|It's first seen in "Ghost Fly" when Jake is killed and appears there after having his heart stopped by BMO. It seems that the way to enter this Dead World is to have unfinished business when alive which is how Jake enters as well as the Ghost Fly.|
|Audio Afterlife||A Dead World that’s all neon and music-like.|
|Temple of Consumption||This level somewhat resembles the Nightosphere, and features a procession of spirits walking into a giant maw.|
|Bird Dead World||This level contains a white lake (which apparently tastes good) and the rest of the area is all spiky. There are Condos of the Dead located here, as well.|
Land of the Dead
Main Article: Land of the Dead
The Land of the Dead (also known as the Underworld) is a location where the souls of living creatures go after they die. Living people can enter the Land of the Dead by staring at a corner where two walls meet and crossing their eyes, which opens a portal. It is unknown whether this land exists in caverns beneath the Land of Ooo, or if it is in another dimension.
Pizza Dead World
The Pizza Dead World is briefly mentioned by Tiffany Oiler, who wanted to go there to "eat [his] feelings".
Glob World is a place first mentioned by Jake in "The New Frontier". He explains that nothing will stop him "from transcending into Glob World" when he tries to accept his croak dream, which showed him that he would die by suffocating in space. His attempt at killing himself fails however, and the Glob World remains a mystery.