Someone finally tried it. In a genre ruled by gags (for an example, see the next-to-last MoMENTOS video), one brave soul marched blindly into the darkness of digestive mystery to discover firsthand what really happens when you chug Diet Coke and then swallow Mentos. And it's not pretty.
But the judges over at the official Mentos Geyser Video Contest did not reward this man's generous act of self-experimentation. Their only thanks for his original research was to disqualify him for failing to use "caution and common sense" in creating his Mentos geyser, a verdict that cost him the year's supply of Mentos (and change of pants) that his service so richly deserves.