Tropes:
- Call-Back:
- Simon is seen recording his last video log, as seen in "Holly Jolly Secrets II".
- Marceline befriends a tribe of animal hat wearing humans or hyoomens like Susan Strong. One has the same bunny hat as the one lying around the ruins in "Beautopia". The band of human survivors explicitly state in this episode that they wear animal hats as protection against vampires - a combination of that vampires only prefer human blood, not animal blood, and because the heavy head-encompassing hats armors their necks against being bitten.
- The humans are running from, among other threats like vampires, "hungry looking rainbows" referencing "Her Parents" when it's stated rainicorns eat humans.
- Marceline apparently picked up the habit of calling out names for her attacks ("Vampire Kick!") from a human girl she befriended in the band of survivors, who enjoyed pretending to be a vampire and shouting out "Vampire attack!" when they played. Marceline does this to remember a friend who has been dead for centuries.
- Cannibalism Superpower: Marceline got her powers by sucking in the dust of the vamps she kills, thus absorbing their powers. It's notable she does this before she's a vampire, since she can still go out in the sun. It's implied to be a part of her demon, "soul sucking" powers.
- Cliffhanger: The vampires all reform while Jake is alone nearby.
- Continuity Nod: Marceline reveals to the Hierophant that she recently obtained healing abilities from slaying the Moon. This is a reference to their fight in the "Adventure Time 2015 Halloween Spoocktacular" comic.
- Double Meaning: The Hierophant calls Marceline a "hapa demon punk". Hapa is Hawaiian word for a mixed race person, (though in certain areas it's supposed to imply some Asian or Pacific Islander descent which might apply to Marceline) in this case referring to both the fact that Marceline is half-demon and that she's been taking on vampiric traits.
- Enemy Rising Behind: The Vampire King is seen coming in from behind the Hyoomans in the flashback.
- Failed a Spot Check: The humans are convinced Marceline is a vampire even after she points out that shes out in sunlight without burning.
- Glamour Failure: The Hierophant can't hide his black boots, which gives him away when he's disguised as Marcy's dog.
- Mix-and-Match Critter: The Vampire King has the head of a lion, the body of a man, the hands of a lizard and the feet (talons) of a bird.
- Mood Whiplash: Simon is filming his video log from "Holly Jolly Secrets: Part 2", breaking down into tears at the end... but the second he stops filming, he cheerfully stops the video and pushes away the camera (which breaks.) Possibly justified as an indication of the crown's influence on Simon making him act like a Mood-Swinger.
- Nice Job Breaking It, Hero: PB's extraction of Marceline's vampirism worked, but brought every vampire she'd absorbed Back from the Dead.
- Orphaned Punchline: We only hear the tail-end of Marceline's mother telling the story of how she met Hunson Abadeer.Elise: ...And then he said "Fine," and that's the story of how I met your dad.
- Shoo the Dog: Marceline tries to shoo everyone else away when she spots the Vampire King in the flashback.
- Shout-Out: During the human refugees' campfire, Two Bread Tom sings the opening theme song of Mr. Belvedere.
- Title Drop: In the flashback, Marceline sings a duet with her Mom where "Everything Stays" is a prominent verse.
- Whole Episode Flashback: All but the first and last minute or so flashes back to Marceline's life as it's apparently flashing before her eyes.
