Years ago, I was developing an audio signal generator for a well-known T&M company that had a 3-second voice ID feature. I was working late when I got the voice record/playback feature working. Before I left for the day, I recorded a message "Help, Let me out of here!" and rigged it to loop, turned up the volume, and covered my headphones with papers.
I was working late the next day, when the night janitor stopped by to tell me that he was quite perplexed as to who was in distress and how he could help!
Classic desktop prank :
I print-screened a colleague's desktop into a bitmap when he was gone for a coffee and made it wallpaper, putting everything on the desktop in a safe place beforehand. We all had fun watching him double-clicking on icons and restarting his pc over and over when nothing seems to work.
I remember one, my boss had a user's manual of a Fuji controller (written in english) and he pass another copy to us (written in japanes) and he started reading the contents aloud. We did not understand a thing...and after surprised faces, he questioned: "can you understand japanese or not?"...later, much more later we discovered the trick...
Somebody was throwing the thermostat next to my bench all the way on or off. SO i out up a sign saying "please don't" to no avail. I was testing battery life on a farm fence charger so I ran the HV loop to a ring around the thermostat and told everybody in the lab. Later that day the president asked me to take it down. I assume got the shock..
In the good old days of DOS based PCAD. I used a editor to change the routine messages on startup of coworkers work stations, "WARNING THIS IS A UNAUTHORIZED COPY OF PCAD AND IS A FELONY IN THE UNITED STATES OF AMERICA. THE PROGRAM WILL BE AUTOMATICLY DELETED."
Way back I used to work my way through college in a 2-way radio shop and there were pranks over the years.
My boss would leave charged axial caps on the bench with the leads folded back across the body so that there was a large area to catch both leads with your fingers when he told you to "Clean up that bench!"
I got him back one day when he was probing the plate on the PA of a 100Watt transmitter. I took an empty clipboard and opened the clip all the way and let it go......
He got back for that by putting a christmas tree flasher in line with the power to a console. I spent 20 minutes removing as many screws trying to figure out why the radio audio cut in and out at a 1/4 Hz rate.
So, one day while rumaging through a garage sale I found these HUGE flash bulbs that used a standard light socket.......... You can guess what happened when the boss came into his dark office the following day and reached for the light switch.
Ok guys, here are my two cents.
What about a button unleashing the obnoxious sound and some sensors to increase the volume as the "victim" walks away XD. He would have to stay closer in order to be safe!