Hey, Free Magic!

 [Riddler has a gun.]

[He sits in his apartment, carefully turning it over in his hands. He doesn't really use guns in the first place--a bit too messy for his taste to work into heists, and he's bright enough to use less lethal things even before he had his powers--but he wasn't about to leave a trophy and weapon in the hands of someone that at least wanted to be a threat. And it is a gun, as much as it looks like harpoon. He can feel that it's more powerful, though it's not quite the same as the faint static of wires and the television and the lights. It doesn't fire bullets, but he isn't sure of anything beyond that. Lasers wouldn't surprise him.]

[He wants to test it, regardless of if he's going to use it again.]

[Instead of going out and hunting for a firing range, or some other clear area, he uses what he can. He simply moves the curtains opens his window and stares up at the other buildings. He's not quite at the top floor, and there's a building across the street with a rooftop garden, where a few sunflowers wave in the breeze near the edge. ]

[Why not. He aims it carefully and fires.]

[And then everything explodes.]

[There's no sunflowers anymore. Or a window to his apartment, nor a wall, and he's flat on his back across the room with the back of his head throbbing. Half the city probably saw that beam.]

[As soon as he realizes what happened, he shoves himself to his feet, grabs his few important possessions--the gun itself, the eyeglass, sharp questions, a simple shirt-and-jeans outfit he left on the bed--and runs.]