Another prank that backfired
Last year, I gave my current roommate a get-off-the-phone excuse machine. You can actually test one here: http://www.prankplace.com/p_excuses.htm
The bottom right button produces a door knocking sound effect, followed by an oriental accented man, loudly proclaiming, “Chinese Food Delivery.” She went around showing some friends this trick gift, and then one day at the hospital (a place sometimes considered a portal for paranormal happenings and where you’re not supposed to carry cell phones anyway) the machine went haywire, incessantly repeating that same phrase, precisely as a Chinese family exited from the elevator. It happened so fast, that she was too stunned to quickly stuff the toy into the drinking fountain or something, and she turned beet red from embarrassment, certain that the folks suspected that she had pressed this button on purpose and kept holding it down!