One time my college roommate tossed a disc (frisbee, colloquially) over past me and, as I was about to catch it, called my name loudly. I woke up a few seconds later on my back, seeing flashing blue, barely making out a staticky voice ask if I needed anything through the sound of his uncontrollable laughter.
He'd timed the "hey, nitsua!" just right to get me to look back and run into a lightpost. But it was one of the blue-light posts on a college campus, and the impact "pressed" the button on the other side to call campus security.