It's a tube for when you mix Coke and Mentos. You screw the tube onto a bottle of Coke, then, while the pin's still in, put in some Mentos. Then you pull out the pin, dropping the Mentos into the soda. The tube helps increase the height of what's going out due to the confined space.I should know, I have one of these! Abusive comment hidden. (Show it anyway.)
I should know, I have one of these!