It's something the writers and the producers over at The Flash have been hinting at for some time now. Our first "easter egg" was thrown in our faces right away in the pilot episode when Barry and Wells pass by a destroyed cage with the name plate reading "Grodd." We next get a little history in a flashback during the episode "Plastique" where we see that five years ago Grodd was a test subject for experiments in the development of mental abilities for interrogation with General Wade Eiling (Clancy Brown) overseeing the work. Eiling wants to take Grodd away from Wells, who refuses, telling Grodd he has other plans for him. More recently in the episode "Crazy for You" we got to see Gorilla Grodd in action as two maintenance workers are show underground in the Central City sewer system which has the name Grodd etched into its walls. They are then brutally attacked by a large ape from the shadows.