The epilogue of The Flash season 1, episode 12, “Crazy for You,” introduced one of the Flash’s most infamous rogues. But was that really a gorilla in the sewer?

Why yes. Yes, it was. That was indeed a gorilla prowling the sewers and killing utility workers. But who exactly is he?

Gorilla Grodd first appeared in DC Comics’ 1959’s The Flash Vol. 1 #106. Grodd is a highly intelligent gorilla with the ability to control the minds of others. He hails from Gorilla City, a secret city in Africa inhabited by other intelligent gorillas. These gorillas gained their incredible intellect from the a space rock that landed in the jungle.

In the New 52 reboot, Barry Allen first encounters Grodd when he’s stranded in Gorilla City after traveling through the Speed Force. The gorillas, except Grodd, believe he is the man mentioned in a prophecy. Grodd, threatened, attempts to kill him but (naturally) fails.

Gorilla Grodd has appeared in numerous comic series outside of The Flash, including Superman/Batman, Birds of Prey, JLA Classified, and Justice League of America. He’s appeared in multiple animated television series as well, including Justice League and Justice League Unlimited, Batman: The Brave and the Bold, and Challenge of the Super Friends.

As one of the Flash’s most popular rogues, it should come as no surprise that The Flash‘s freshman season has planted seeds about his existence.

In the pilot episode, Barry and Harrison pass a cage with bent bars labeled “Grodd.” It’s likely Grodd escaped from S.T.A.R. Labs in the chaos when the particle accelerator malfunctioned. A flashback in “Plastique” also indicated that Grodd was one of General Wade Eiling’s experiments for creating advanced, telepathic interrogation techniques.

So did S.T.A.R. Labs’ experiments give Grodd his powers? Or was it the particle accelerator?

And does that make Grodd our first meta-animal?

In terms of when we can expect Grodd to make his presence known, The Flash executive producer Greg Berlanti says, “The comparison I make is a little bit to Slade the first year on Arrow in the sense of we started with the mask in the pilot and then we saw which way we were going.” Slade Wilson was, of course, the Big Bad of Arrow‘s second season.

Berlanti adds, “He was, ultimately, in the back half of that first season even more than we would ever do with Grodd this first year because… We’re going to have to get the technology right and all the stuff right to make it look and feel real. But a lot of times, we do this stuff not as a tease as much as a challenge to ourselves of, ‘Can we do it?’ Grodd’s definitely one of those, so we hope we pull it off.”

The Flash airs Tuesdays at 8:00 p.m. ET on The CW.

Are you looking forward to more Gorilla Grodd on ‘The Flash’?