When my friends and I decided we would go camping next to a lake when we were younger--ALL BY OURSELVES (we were probably 13 or 14), my parents snuck in with a box of dry ice and dumped it in the lake right next to our site--then made noises...

Suddenly, there's scary noises and a weird mist and the water next to our site was bubbling! Then, they jumped out and scared us

Definitely made for a neat-looking rest of the evening.