When you take a photo without flash, everything's normal. Turn on the flash and suddenly your friend becomes a literal superhero traveling at the speed of light. The double meaning here is chef's kiss—"Flash" as in camera flash, and "Flash" as in the DC Comics speedster who looks like he's made of pure lightning when he's running. The flash photography literally reveals The Flash. It's the kind of pun that makes you groan and laugh simultaneously, which is basically the pinnacle of dad joke evolution. Also, fun fact: The Flash can run so fast he can phase through solid objects and travel through time, but apparently he can't escape being photographed looking absolutely terrifying.