Star, Marco, Janna and Tom lose their memories as they traverse amnesia-inducing waters to get back to Mewni.
Tropes:
- Bottle Episode: The episode primarily takes place in the realm of magic within Oskar's car.
- Call-Back: As Eclipsa's spells feared in "The Spell With No Name", the titular spell really is starting to spread across dimensions. Moon washing the corruption it caused off of herself the last time she was in the Realm of Magic, which a young unicorn was seen drinking from, has spread and corrupted most of the unicorns living there.
- Cliffhanger: The Firstborn is attacked by another unicorn affected by the The Corruption, forcing her to send everyone else out with a Blind Jump, and it's left unknown if Tom was also sent away.
- The Corruption: It's revealed that the Magic Dimension is being corrupted again, this time by the cast off residue of Moon casting Eclipsa's Spell with No Name. The Unicorns are being turned into dark and deranged versions of themselves.
- Double-Meaning Title: Star is a "mama" both in that she refers to the Firstborn as her daughter and starts playing house with the baby unicorns when she loses her memory.
- Failsafe Failure: The party child-locks the car to keep themselves straying after they lose their memories, but Tom just blows the whole top of it off as soon as he wants out. The seatbelts prove to be more of a hindrance.
- Forbidden Chekhov's Gun: Star refuses to let the Firstborn use her teleportation spell again because they don't know where in Mewni they'll get sent. The corrupted unicorns' attack forces her to do so anyway.
- Higher Understanding Through Drugs: While traveling through the realm of magic, everyone starts getting disorientated by the realm's amnesia effect. While under the effects, Marco starts muttering to himself while losing his memories and soon has an epiphany; he's only doing this because he's in love with Star (not like Tom who's doing this to get home, and Janna who's doing it for the sake of weirdness).
- Kids Driving Cars: Played with briefly when the group go through their haze and think the Firstborn is keeping them prisoner in the car, with Star on the floor pressing the gas pedal with her hands while Marco steers from the passenger seat.
- Last of His Kind: The Firstborn becomes the last one not affected by Moon's corrupt magic that was left behind with the remaining newborn unicorns become corrupted after they drank the dark magic.
- Lotus-Eater Machine: Again, the Realm of Magic has this effect. Visitors start losing their memories and end up wanting to stay. However, the Firstborn wants them gone since Star has been nothing but trouble since she arrived.
- Love Epiphany: As Marco's memories begin to fade, he has a monologue about being close to Star before finishing with "Because I love you, Star."
- Mushroom Samba: The whole episode is an allegory of Star, Marco, Tom and Janna going on a drug-fuelled road trip.
- Power Incontinence: Halfway through their amnesiatic haze, Tom suddenly erupts, blowing the top off of the car. He then continues the rest of the episode on-fire with a Voice of the Legion and a Nightmare Face, having had no idea he could do these things and unable to figure how to stop it.
- The Reveal: Marco deduces that the first Mewman settlers might have been humans who stumbled into the Realm of Magic and wound up on Mewni, which would be consistent with the ones Glossaryck and Meteora encountered in "Meteora's Lesson".
- Something We Forgot: Star, Marco, and Janna manage to take off their seatbelts, but Tom doesn't, and then the former three forget him and get sent away at the end of the episode, and it can be assumed he forgot them too.
- Truth Serum: It's complicated whether or not Marco was genuine in his confession of love to Star. He was in a haze of amnesia and could've gone just as mad as the others. Did he just lose the memory barriers guarding that particular thought?
- Wham Shot: Marco deduces from the carvings on the cave wall that the original Mewman settlers came from Earth. The others completely ignore this revelation.
