Mark Rolston, Peri Gilpin, and Jose Yenque reprise their roles of Firefly, Volcana, and Copperhead, respectively.
During John Dee's opening dream, many villains make special cameos: the Joker, Lex Luthor, Shade, Cheetah, Grundy, Gorilla Grodd, Deadshot, Simon Stagg, Star Sapphire, and the Ultra-Humanite.
(J'onn apparently is meditating)
The Flash: What were you working on?
J'onn: Nothing. I was taking a nap.
Copperhead: Are you crazy?
Solomon Grundy: No – mad!
Copperhead: I'm so dead...
Volcana: (about Firefly's flamegun) That’s your flamethrower?
Firefly: Wait 'til you see how I use it...
The Flash: Say no more!
Batman: Wasn't intending to.
Batman: Get over here!
The Flash: Crankier then usual...