Marco goes to Mewni to find Star and runs into King River, who is tasked with keeping morale high while the Queen is away.
Tropes:
- 0% Approval Rating: The Mewnians hate King River because he's so busy partying that he's neglected to provide the kingdom with basic needs, such as taking out the garbage or putting out fires.
- Affectionate Nickname: River is revealed to have one for his wife, calling her "Moon pie".
- Bait-and-Switch: At first it looks like River is wallowing in despair, as Marco was in the first episode of the season. But when he plays his record player, instead of sad music, he plays a loud dance track and gets up to party all day long. But then we find out that he's partying because he's depressed over the absence of Moon and Star.
- Bread and Circuses: A non-malevolent example. River tries to keep his subjects happy by holding parties with them. Much of it is to distract himself from worrying about Star and Moon.
- Character Development: Much of this episode is one for River as he learns to be a better leader without his wife.
- Flat "What": This is Marco's reaction when River tells Foolduke to "fetch us our loincloths".
- Impact Silhouette: River looks forlornly at Queen Moon's side of the bed, where her pillow not only has the impression of her head, but marks from her lipstick and mascara as well.
- Limited Wardrobe: Before leaving with Star, Moon left River with dozens of copies of his usual outfit.
- Non-Malicious Monster: The monster just thought King River was inviting her, and leaves peacefully once the confusion is cleared up.
- Poor Communication Kills: The monster only came towards the castle because she thought King River was telling her to come closer.
- Rousing Speech: King River gives one to the Mewmans to get them to fight back against the approaching giant monster.
- Earlier in the episode, Marco gives River one to him when he starts to feel like a failure to his people.
- Sarcastic Clapping: Ludo as he interrupts the celebration for King River.
- Tempting Fate: River assures his subject that the monster can't cross the magical force field that protects Mewni. Unfortunately, the shield is so degraded that the monster is able to step over it. It also gets past the magic moat (which is all dried up) and the magic safety cones.
- Unwitting Instigator of Doom: The only reason the monster was advancing through Mewni is because he thought King River was summoning him closer, when in fact he was telling him to go away. The constant partying for days on end has also left Mewni's soldiers in no condition to resist Ludo and his rat army (or the giant monster before that).
- Wham Shot: Just when it looks like the episode will end on a happy note, in comes Ludo with his rat army to take over.
- Your Favorite: Marco comes to Mewni with the excuse of giving to Star a box of her favorite cereal from Earth.
