Check out the neat image that the Gotham TV series posted on their official Twitter account.
It's Edward Nygma transforming into the Riddler.
The Gotham TV series deals with the origins of the characters, hence "Before There Was Riddler..."
Hit the play button on the image to see the effect:
GOTHAM is an origin story of the great DC Comics super villains and vigilantes, revealing an entirely new chapter that has never been told. From executive producer/writer Bruno Heller (“The Mentalist,” “Rome”), GOTHAM follows one cop's rise through a dangerously corrupt city teetering on the edge of evil and chronicles the birth of one of the most popular super heroes of our time.
GOTHAM is based upon characters published by DC Comics and is produced by Warner Bros. Television. Executive producer Bruno Heller (“The Mentalist”) wrote the pilot, which will be directed and executive-produced by Emmy Award nominee Danny Cannon (the “CSI” series, “Nikita”).