Yes, that was Firestorm in tonight's episode of the Flash.
Video interview with Grant Gustin about the Arrow and Flash crossover
Interview with Carlos Valdes about the Flash and Arrow crossover.
Extended promo trailer for the Flash vs. Arrow crossover
Interview with Danielle Panabaker of The CW's Flash about the crossover with Arrow
Interview with Executive Producer Andrew Kreisberg about the Flash and Arrow crossover
Screen captures from a preview clip from Flash vs. Arrow
Ratings report for the Flash episode Power Outage
Nuklon, Fire, Damage, Elongated Man, Amazing-Man? Just another day at the office for the Flash writers.
Screen captures from a new trailer for the Flash vs. Arrow crossover.
