I, Simon don't remember you, Marceline
Marceline reluctantly hangs out with the Ice King and helps him write a song.
- Adult Fear: Knowing you're going insane and becoming a danger to yourself and to those who love you.
- Artists Are Attractive: Ice King attempts to invoke this trope. It doesn't work.
- Broken Bird: One of Marceline's saddest moments in the series.
- Ice King sings one of Marceline's songs, calling back to that same moment in "Holly Jolly Secrets".
- Remember the teddy bear Marceline used to have till Ash sold it? Ice King, back when he was Simon, gave it to her.
- Cerebus Retcon: The reason why Marceline keeps changing places is because she feels the need to constantly escape from a father figure who no longer remembers why he cares so much about her. We also learn that the loss of Hambo the teddy bear made her upset due it being the only thing she had remaining from her childhood, and by extension, a once lucid Ice King.
- Does This Remind You of Anything?: The relationship between Marceline and Ice King is reminiscent to many fans of a relationship between a younger person and a severely demented elderly relative.
- Downer Ending: Marceline reads out a letter written to her by Simon Petrikov for the first time, explaining in detail why he had to abandon her during her adolescence. That, combined with her trying and failing the whole second half of the episode to make the Ice King remember who he was, makes her breakdown crying. The episode ends with a sobbing Marceline singing out the letter as lyrics to a song that an obliviously happy Ice King is playing, before cutting to a flashback of Marceline when she was a crying little girl alone just after the apocalypse. Simon finds her, wipes away her tears, and gives her the teddy bear that she eventually loses in "Memory of a Memory".
- Freeze-Frame Bonus: Marceline shows the Ice King a picture of his old self, Simon Petrikov, from a newspaper clipping about him. In the picture, Simon is holding the Enchiridion.
- Incest Subtext: Unintended on Ice King's part, since he doesn't remember, but Marceline sees Simon as a surrogate father, which adds an extra layer of heartbreak and Squick when the Ice King comes on to her after they hug.
- Minimalist Cast: Jake, Finn, Ice King, Marceline and Gunter.
- Rhetorical Question Blunder: When Ice King sings the lyrics "Gunter, do you even love me?" in his "Fry Song" cover, Gunter readily affirms it only to be told by Ice King that it was rhetorical.
- Sanity Slippage: Further explored on Ice King's descent to madness in that his decaying mind made him a threat to Marceline, which is why she doesn't see him anymore.
- Shout-Out: Jake's delivery of the line "Your constant harassment of the female gender makes me sick" is an impression of Diedrich Bader as Batman in Batman: The Brave and the Bold.
- Villains Out Shopping: Finn and Jake see Ice King lying on the floor tangled up in wires and Marceline beside him and assume Marceline fought him to prevent him from doing something evil. Actually Ice King was just asking her for help working on a song and tripped over the wires.
- Wham Episode: Ice King used to know Marceline. Also, confirmation that the show takes place in a postapocalyptic setting.
- Wham Line:
: You don't remember anything, do you, SIMON?!
- Wistful Amnesia: Ice King can't remember ever being Simon, but still senses that he has a "tortured past".