: Katie Cassidy appears as Black Siren, the Earth-2 doppelgänger of Laurel Lance (Black Canary) [2, 15]. She leads Zoom's army and is eventually defeated by a vibrational frequency device that neutralizes Earth-2 inhabitants [2, 9].
: Following his recent experience in the Speed Force, Barry exhibits a "zen-like" and potentially dangerous level of confidence, believing the universe is on his side [6, 10, 21]. [S2E22] Invincible
The episode concludes with a major turning point leading into the season finale: : Katie Cassidy appears as Black Siren, the