Under the control of Red Kryptonite, Kara Danvers is brainwashed by rock 'n roll front man Ra's Al Ghul and sent on a mission to purify the world... starting with the terrible music of Karen Beecher's favorite boy band!
Tropes:
- Arson, Murder, and Jaywalking: Among the effects of red kryptonite listed by Karen's computer are fits of rage, depression, monstrous transformations, subjectivity to mind control, and bad acne.
- Art Shift: At the end of part 1, the art shifts to a more simplified version as Supergirl is brainwashed.
- Dance Party Ending: The episode ends with the Super Hero Girls dancing with Hal, Barry, and Garth onstage while Ra's escapes the stadium.
- Evil Costume Switch: While under Ra's Al Ghul's mind control, Supergirl's costume gains a sinister looking red and black color scheme. It changes back to normal once the spell over her is broken.
- Evil Is Petty: The first "atrocity" the League of Shadows decides to get rid of is a boy band whose music they don't like (and it's not even objectively bad).
- Glass-Shattering Sound: While he, Hal and Barry are singing "Save You With My Love", Garth belts out a high note that shatters Kara’s Red Kryptonite necklace.
- Hypno Trinket: Ra's's "lucky guitar pick" is actually Red Kryptonite, and uses an identical rock to influence Kara into destroying stuff.
- Hypocritical Humor: Hal wastes no time mocking Up Past 8 and anyone who likes them, but when pretending to be in said boy band, he indulges a little too well.
- Karma Houdini: Ra's is able to escape punishment for his actions, only losing his ability to use Supergirl as an attack dog.
- Kryptonite Factor: Kara gets controlled by Red Kryptonite.
- Mind-Control Music: Played with. Ra's Al Ghoul sings to get the Red Kryptonite to turn Kara (slightly) more rude and violent than usual. At the Up Past 8 concert, Kara has been singing the same song, which lets Bumblebee know that it will take other music to drive it out of her head.
- Mugged for Disguise: Hal, Barry, and Garth steal the outfits of Up Past 8 to pose as them during the show, and Bumblebee ties them up and hides them backstage. They're still willing to pose for a selfie with her.
- Mythology Gag: While the Red Kryptonite here is used to make Kara act evil, now its most widely known use thanks to shows like Smallville and Supergirl, Karen's AI assistant mentions the various weird effects it's had in the comics.
- Not Hyperbole: Ra's sings about wanting to purify the world, and clarifies that his lyrics aren't metaphors.Ra's Al Ghul: We will purify the world of all atrocities! And all who remain will be ruled by me!
Karen: Kara, are you hearing this?
Kara: What? It's just metaphors, they don't really mean it!
Ra's Al Ghul: Our lyrics aren't metaphors, we really mean it! Literally! - The Power of Friendship: The girls try to get through to Kara with a mix of this and…
- The Power of Rock: Kara's mind control is broken by Hal, Garth and Barry singing an Up Past 8 song.
- Villain: Exit, Stage Left: Ra's escapes after his Hypno Trinket is broken, leaving behind his cultists, who are dancing along to Up Past 8 in their hiding place.
- Villain Song: Ra's gets two. "Literally, Listen to Me", and "You're Mine."
- Weirder Than Usual: Karen feels that Kara is acting a bit off. Barry doesn't think she's acting any differently at all.
