We've been teased with the promise of meeting Grodd since the very first episode of The Flash [1], and this week, he makes his debut in a big way. The title of the episode is "Grodd Lives," so we kind of knew it was coming, but still. There have been a lot of different storylines throughout the first season of The Flash, so as a refresher, let's take a look at everything we know about this big, bad gorilla so far. Spoiler alert: he hates bananas.

• Yes, he's really a gorilla. Grodd is a gigantic gorilla that General Eiling and Harrison Wells had been testing at S.T.A.R. Labs. Wells, who is apparently slightly more humane than General Eiling, stops the experiments when he realizes how cruel they are. Grodd escapes during the particle accelerator explosion, which takes place before the series starts. This means he's been in hiding for the whole season. So, where has he been?
• He's no ordinary gorilla. When the gang captures General Eiling, they realize he's not in his right mind. His words don't make sense, and that's because Grodd is in his brain. In addition to being generally huge, Grodd is hyperintelligent and has telepathic powers that allow him to control people. He can even control their bodies; Joe almost shoots himself in the head. We don't know how closely the show will follow Grodd's origin story from the comic books, but in the DC universe, Grodd's powers come from an alien ship that crashes in his home.
• He's been living in the sewer. For the past several months, Grodd has been holed up in the sewer system, growing angrier and smarter.
• Aside from Wells, he's The Flash's biggest enemy. The Flash has superspeed, but Grodd has about 500 pounds on him. He's well-matched in terms of intelligence, but Grodd has the ability to get into The Flash's head — as long as The Flash isn't wearing that magic crown that Cisco constructs.
• He's still out there, and he's mad. The episode ends with Grodd getting hit by a train. It's highly unlikely that he dies, but he probably needs to lick his wounds before he comes up with a revenge plan.