This is a video from a lake in California's Sierra National Forest of a bunch of water boatman bugs (Corixidae) freaking out and jetting forward every time a man yells "Hey!", presumably because they think that's God telling them he's about to kill them all. Or at least that's what I think every time somebody yells hey at me.
The lake has very few, if any, fish in it, so a huge population of water bugs, mostly Corixidae (from what we could see). For whatever reason, the ones that happen to be on the surface when we shout shoot forward rapidly when they hear a loud voice. The ones that are underwater don't react at all. They don't react to a clap. The only thing that got a reaction out of them was shouting. They seemed to prefer "Hey!" You could actually "see" the speed of sound by watching their reaction propagate across the lake.
Are you thinking what I'm thinking? "Usually not." We should go camping together sometime! Thing of all the fun we'll have -- swimming, fishing, cooking beans and weenies -- sleeping under the stars. "Admittedly that does sound nice." Tying ourselves to a tree covered in honey. "Um, what?" You've never played the Goldilocks game before?! It's even scarier than telling ghost stories around a fire!
Keep going for the video.
Thanks to Arman, who agrees that looks like a great lake for skipping stones. Man, that is like, one of the few things I'm good at (plus losing my balance and falling in and ruining my phone).