Hajime, a young man from Japan, wanted to make a unique experiment. First, he filled his tub with Diet Coke. To make things more interesting, he added a whole bunch of Mentos candies to the mix. Then, he dived in and prepared himself for an explosive bath.
The Diet Coke and Mentos geyser or The Mentos eruption is a reaction between the carbonated beverage Diet Coke and Mentos mints that causes the beverage to spray out of its container. This is what theory says, but as we all know, practice is always more fun. Just watch this guy: