Justice League: 29 Easter Eggs & References You Need To See

23. Gorilla Grodd

When Bruce first meets Barry, Barry mentions that he's "fluent in sign language...gorilla sign language", which at first seems like a disposable, goofy gag demonstrating just how much of a socially awkward motormouth Barry is.

However, comic book fans will no doubt appreciate this as a reference to one of DC Comics' more eccentric antagonists, The Flash's longtime nemesis Gorilla Grodd.

While it's highly unlikely the DCEU will ever dare feature a villain as goofy as the super-smart gorilla himself, this was a fun way to imply that The Flash may well have had a run-in with him before (or at the very least, pushed him over and run away).