When I was a freshman at Rutgers (1969) I happened to read a book (Heinlein's "Farnhams Freehold") where the hero used a mixture of ammonia and some kind of iodine compound to make nitrogen tri-iodide, an extremely powerful and volatile compound, but only when dry. When wet, it can't be set off very easily at all. My father was an organic chemist so I ask him about it and then got the necessary ingredients during one of my chem labs. I mixed it into a dilute solution.
Then I sprinkled droplets of it all up and down the stairs of our dorm as well as around the door frame of one of the unpopular students who always slammed his dorm room door when he entered. Once the solution dried, the stage was set.
Guys coming back from classes and up the stairs set off the dried droplets by friction from their shoes, making a small and harmless (but very surprising) explosive puff. Everybody got a good laugh at others' plight, but the kid who came back and slammed his door as usual, was quite a bit more surprised, and most probably soiled his shorts. He heard the peals of laughter outside his door and knew he'd been had.
My father told me that this was a popular college prank in the 1940's, when they would spread droplets over the dance floor a few hours before a dance. You can guess the result.