If you have enemies, snowmen or not you can make a messy explosion using soda and mentos. You've seen the soda fountain created when mentos are put into a 2 liter soda bottle now if you can get enough pressure inside to make it explode you'll have a soda bomb.
Open up the Diet Pepsi bottle and pour out enough so the level of Pepsi goes down about an inch.
Glue five Mentos to the inside of the cap. (You might have to shave a little off the sides of the Mentos to make it fit in the cap, you're going to have to put the cap back on.)
Put the cap back on. Make sure the Pepsi doesn't touch the Mentos! (Until you are ready to throw you might want to put another cap on that doesn't have Mentos to avoid unwanted explosion.)
Throw far away. It'll explode when the Pepsi and Mentos mix.