The episode ends on a downer note; Bizarro is defeated and returned to an artificial coma at the DEO, with Kara feeling deep sympathy for the "innocent" girl Lord used as a weapon. The final scene sets up the next episode as Kara returns home to find a strange, tentacled "Black Mercy" creature on her ceiling. Supergirl (2015) S1E12 "Bizarro" Recap - TV Tropes
: Maxwell Lord finally reveals his secret experiment: a clone by conversion designed to destroy Supergirl. It took seven failed attempts—resulting in the deaths of the previous subjects—before this "Jane Doe" successfully survived the procedure. [S1E12] Bizarro
: Mirroring classic comic book lore, Bizarro possesses powers that are the inverse of Kara's: Freeze Vision (purplish) vs. Kara's blue Heat Vision. Flame Breath vs. Kara's Arctic Breath. The episode ends on a downer note; Bizarro
: Kara struggles to balance her duties with a burgeoning romance with Cat Grant’s son, Adam . After Bizarro interrupts their date and endangers the city, Kara realizes she cannot maintain the masquerade and breaks up with him, which also strains her relationship with Cat. It took seven failed attempts—resulting in the deaths
: The DEO discovers that since Bizarro is a molecular opposite, standard green Kryptonite actually makes her stronger and mutates her skin. J’onn J’onzz suggests reversing the ionic charge of green Kryptonite to create a blue-toned substance that can incapacitate her. Personal Stakes
: Lord manipulates Bizarro into believing Supergirl is "bad," leading to several high-stakes Beam-O-Wars where they pit their opposing abilities against one another.