Instructables user Britt Michelsen has lately been experimenting with fluorescent materials, including riboflavin. She decided to use it to make a food that looks like kryptonite. Michelsen made a mold out of aluminum foil, cooked riboflavin into sugar, and poured it into the mold. The result was a glowing candy that looked quite like the lethal substance in the Superman mythos.

Link via Make

Previously by Britt Michelsen:
Pixelated Trash Can
"You Killed Kenny!" Doorstop