According to "The Flash" showrunner Andrew Kreisberg , the classic 1950's DC Comics' super-villain 'Gorilla Grodd' appears in the "Plastique" episode of the series, airing November 11, 2014 and we have the image to prove it:
'Gorilla Grodd' debuted in DC Comics "Flash" #106 (April–May 1959), created by writer John Broome and illustrator Carmine Infantino.
"...originally an average ape, 'Grodd' was imbued with super-intelligence by the pilot of an alien spaceship, that crashed in his homeland of Africa. Grodd's psionic abilities allow him to place other beings under his mental control.
"Grodd can also project telekinetic force beams, telekinetically transmute matter and transfer his consciousness into other bodies..."
"Plastique" is written by Aaron Helbing, Todd Helbing, Brooke Eikmeier and directed by Dermott Downs.
"....after a bomb goes off downtown, the army, led by General 'Eiling' (Clancy Brown), rolls in and takes over the case, much to the surprise of 'Joe' (Jesse Martin).
"Suspicious, Joe tells 'Barry' (Grant Gustin) that he and his friends at 'S.T.A.R. Labs' should look into the army’s involvement. 'Wells' (Tom Cavanagh) informs the team that Eiling was experimenting on his men to turn them into super soldiers.
"'Cisco' (Carlos Valdes) confirms one of Eiling’s soldiers, 'Bette Sans Souci' (Kelly Frye), was at the bomb site.
"'The Flash' tracks her down and realizes she's not setting off the bombs, but is a 'meta-human' who can blow things up real good, just by touching them.
"Meanwhile, when Joe learns Iris is writing about 'the streak', he tells Barry to make her stop. Barry realizes Iris won’t listen to him so he decides to have The Flash pay her a visit..."
Click the images to enlarge and Sneak Peek "The Flash: Plastique"...