If he'd used Pop Rocks, he'd be dead.
This video comes to us from YouTube user Hajime, an young Japanese man who clearly loves sugar, based on both the amount of sweets in his house and his personality. The Coke Zero is probably just so he doesn't explode.
As you can see above, Hajime took it upon himself to cover his torso in Mentos, fill his tiny Japanese bathtub with Coke Zero, and jump in. The chemical reaction results in the grossest-looking jacuzzi of all time. But when you think about it, it's probably the least gross jacuzzi of all time. Most of them are bacteria incubators, but I don't know if any life could survive in that synthetic cocktail of preservatives and high-fructose corn syrup. In tomorrow's world of drug-resistant superbugs, we'll probably all bathe like Hajime.