The Turtles and Angel venture into a spooky house to track down Angel's missing brother.
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!! This episode provides examples of

* ActuallyIAmHim: The caretaker reveals that he is C.F. Volpehart after the Turtles defeat the monster.
* AllJustADream: Leo realizing this allows him to break free.
* AndIMustScream: Basically what C.F. Volpehart's life became. He eventually reformed and wanted to kill the monster, but he had spent too long under its grasp, so he was helpless to act. Being immortal, this suffering persisted until the Turtles won.
* BigNo: Leo gets one when the monster shows him an image of Master Splinter being killed. We actually see it twice: one in the HowWeGotHere ColdOpening, and then repeated in the episode proper.
* BittersweetEnding: The Turtles defeat the Necro Monster and save Angel's brother Ryan, which also allows C.F. Volpehart to finally pass away, but the Necro Monster is evidently still alive and ready to continue its manipulations.
* BodyHorror: In Mikey's nightmare, Leo has tentacles where one of his arms should be.
* DarkerAndEdgier: Probably one of the darkest episodes of the entire series.
* DealWithTheDevil: How C.F. Volpehart gained his wealth.
* EldritchAbomination: The Necro Monster, which heavily resembles Cthulhu, and is a creature that has been manipulating mankind since it arrived on Earth, and is evidently immortal both in age and the fact the creature is still alive despite the Turtles defeating it.
* TheEndOrIsIt: The ending of the episode shows the monster taking possession of a random person after its apparent defeat, with that guy now servings as its vessel.
* EtTuBrute: Mikey's worst fear is betrayal.
* {{Flashback}}: Showing how the monster came to Earth and how Volpehart became its servant.
* {{Foreshadowing}}: The caretaker saying he's seen stranger things than the Turtles.
* IgnoredExpert: The caretaker constantly warns people to stay away, and they never listen to him.
* IncorruptiblePurePureness: The Native warrior. Also, Leo in the end.
* LovecraftLite: While the Necro Monster is evidently still free to manipulate humanity by the end of the episode, the Turtles still manage to defeat it and save Angel's missing brother.
* MythologyGag: Raph being in the Shredder's armor is a nod to a plot-point in Image's third volume series.
* NeverSayDie: Averted. The caretaker tells the Turtles, who are battling a horde of zombies, that they cannot kill the dead.
* NoImmortalInertia: What happens to C.F. once the monster is killed.
* NobleSavage: The monster can tempt the greedy, but its meteor crashed near a Native American tribe that could not be swayed and who set about building a weapon to kill it.
* NoNameGiven: The monster itself is not named on-screen but credits and other official sources reveal it to be the "Necro Monster".
* OhCrap: Defied. Much to Donny's surprise, the caretaker isn't the slightest bit surprised to see four giant, talking turtles because he's seen far stranger.
* PoliceAreUseless: Angel tried getting help from the police but they refused to look her brother because they needed to use the resources to rebuilt after the Triceraton invasion.
* ReallySevenHundredYearsOld: The caretaker is revealed to be C.F. Volpehart, given immortality from the monster a thousand years ago.
* RedEyesTakeWarning: Everyone under the monster's influence and the manifestations it creates.
* ReducedToDust: The caretaker turns out to be C.F. Volpehart, cursed with immortality. Once the Turtles defeat the monster, he disintegrates into dust. Onscreen. Then Mikey walks on the dusty remains.
-->'''Mike:''' Hey, where's the old dude?\\
'''Angel:''' You're standing on him.\\
'''Mike:''' Eh? ''(Looks down at dust under his feet)'' Eew! Gross, gross, gross!
* SignificantAnagram: C.F. Volpehart/ Creator/HPLovecraft.
* SpannerInTheWorks: The native warrior was ready to slay the monster, but then C.F. Volpehart arrived.
* SpiritualCrossover: This episode features the Turtles going up against the Necro Monster, who's basically a stand-in for [[Literature/TheCallOfCthulhu Cthulhu]].
* TheEndOrIsIt: The monster survived and successfully tempts a businessman into being its servant.
* WhamLine: "My name is C.F. Volpehart."
* WhatDoTheyFearEpisode: After the Turtles are captured, they are forced to endure their worst nightmares.
** Leo both failing to save Splinter's life and being denounced by him as a disappointment -- being a failure.
** Donny failing to save Angel from falling to her death -- watching a loved one die.
** Raph being just like the Shredder -- losing to his anger.
** Mikey facing a version of Leo that took the monster's offer and underwent BodyHorror -- being betrayed.
* WhatYouAreInTheDark: During the climax, the others are knocked out, so Leo is forced to face the monster alone. Saying Leo can't win, the monster offers him anything he desires if he becomes his servant. Leo is briefly tempted, but he breaks free and strikes the monster with the spear.
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