I just watch [The Flash](series:1068303) and I freaked out at the end.
In episode 5 "Plastique" torwards the end we saw a flash back of Dr. Harrison wells talking to a gorilla with a name plate with the specific word Grodd
But when we were walking through the halls of STAR labs in episode 1 we saw that grodd's cage was busted and broken. With all these easter eggs over a long period of time you start to wonder if grodd is actually coming to the Flash. until we got a hint from a picture posted by Grant Gustin. It showed him being held by a person in a gorilla costume. Possibly a hint to grodd making an appearance. Finally tonight we have our answer. After they got the teleporter it cut off to two men in the sewers. They find a wall and see the word GRODD repeated and then a sound makes them look. They don't see anything but when they turn around there is a huge gorilla (grodd) and he takes the two men deeper into the sewers then it goes black.