Back when I was a kid, everyone knew that Pop Rocks and Coke were a lethal combination. Word on the street was that Mikey from the Life cereal commercials had flown too close to the sun of sugary goodness, ate both at once, and had his stomach explode out of his torso.
This, of course, was total sleepover ghost story baloney. Mikey is fine. Pop Rocks and Coke will do nothing in concert beyond rot your teeth. But, apparently, Diet Coke and Mentos CAN be combined for explosive results:
No one's been injured by eating this combination of foods that we know of, probably because the physical reaction is so strong and so sudden that it's pretty much impossible to swallow them before they expel themselves from your mouth (watch this video to get a sense of it). But let's this be a warning to all you daredevils: do not try this at home. Unless you plan on putting it on YouTube. Then it's a good idea. A very good idea.