Finn and Jake must commit a cosmic crime in order to find Finn's father.
Tropes:
- Arson, Murder, and Jaywalking: The kinds of criminals in the Citadel include head-stealing monsters, planet destroyers... and what appears to be a shady politician.
- Continuity Nod: Peppermint Butler's friendship with Death comes up again, after "Death In Bloom".
- Family-Unfriendly Death: Old Man Prismo is reduced to ash on-screen.
- Foreshadowing: "Yeah-or maybe he was ambushed in the wild and hid you, so you wouldn't be captured too." Jake was half-right in 'The Island' Miniseries.
- Heroic Sacrifice: Prismo is willing to sacrifice himself to help Finn and Jake find Finn's biological dad, saying it's okay because he'll still be around as long as the old man who dreams him up is still alive. Unfortunately, the Lich takes advantage of the fact that Prismo thinks he's harmless to kill his host body and hitch a ride to the Citadel.
- Homoerotic Subtext: Jake and Prismo noting how happy they always both are when they're together. Prismo's attachment to Jake is so strong that he's willing to be non-existent for a thousand years to help Jake and Finn.
- I'll Kill You!: After the Lich kills Old Man Prismo, Jake flies into a rage, Hulking Out and shouting "Lich! I'm gonna kill you!"
- I Need to Go Iron My Dog: Cosmic Owl excuses himself when he gets nervous about Finn and Jake's talk of cosmic crimes, saying he has to go preen his feathers.
- Living Dream: Prismo is actually a dream of a sleeping old man who lives on one of the asteroids outside his room.
- Oh, Crap!: Upon seeing the Lich intends to wake up and kill his host body, Prismo panics and says "Wait, I changed my mind!" before he fades away.
- Pals with Jesus: At the beginning, Jake is hanging out in Prismo's room with other cosmic entities, including the Cosmic Owl, Grob Gob Glob Grod, and Death. And Peppermint Butler.
- Sealed Evil in a Can: The Lich is trapped in Prismo's room and is unable to kill anyone in it. As the Lich is so focused on the goal of killing everything in existence, he does absolutely nothing and doesn't aknowledge anyone in the room until he has a way to be free of Prismo's time room. It's not that the Lich couldn't do anything so much as the Lich didn't want to do anything and did not care about anything beyond its goal.
- Soul Jar: Prismo's true form is an old man. As long as his true form is asleep, he exists as a wish granting Living Shadow.
- Stock Audio Clip: The sound made by the dark Prismo-like creatures is Marceline's snarl from the opening sequence.
- Tempting Fate: Prismo assures Jake "What could go wrong?" right before the Lich comes back to life and kills Prismo himself.
- Title Drop: The Lich shouts "Wake up!" as he shakes Old Man Prismo awake.
- Wasteful Wishing: Since they already used up their Prismo wishes, Finn and Jake bring Shelby to wish to see Finn's dad for them. He wishes for a pony for his girlfriend instead.
- Weakened by the Light: The shadowy Prismo-like entities released when the old man stirs in his sleep are destroyed by the penlights Prismo gave to Finn and Jake.
- Wham Line: After being told the whole time to not wake the old man up, they get him back to the Time Room... and Prismo tells them to wake him up. When they ask why:Prismo: Just wanted one last look at myself.
