: Fans were treated to a darker take on Laurel Lance via Black Siren , a character who would go on to become a series regular in later seasons of Arrow .
To combat the overwhelming number of Earth-2 invaders, Cisco and Wells develop a frequency-based weapon. They realize that Earth-2 inhabitants vibrate at a different frequency than those on Earth-1. By setting off a refined sonic pulse across the city, they manage to render all Earth-2 meta-humans unconscious simultaneously, allowing the police to apprehend them. [S2E22] Invincible
: Critics at IGN and The A.V. Club praised the episode for its emotional weight and high stakes leading into the finale. : Fans were treated to a darker take