Yeah, that's really clever, covering your own kitchen with ketchup. Maybe for an encore he could flood the bathroom or get the drains to back up.
Anyway, one of my personal favourites.
When I was in the 6th form, and in the year between school and university, I had a part time job at the local Tesco store. The managers there were right ******s, so on my last day there I decided to play a practical joke on them.
I went into the gents toilets next to the staff canteen, into one of the cubicles. Removed the cistern lid. Flushed the toilet. Held the ballcock up to prevent the tank filling. Stabbed a hole in the bottom of the ballcock with a screwdriver. Wedged an empty toilet roll tube under the ballcock to keep it in the 'up' position and keep the tank empty. Replaced the lid, making sure to leave it slightly displaced. And then left.
It turned out that my trap was sprung by the butchery manager, which was great because he was the biggest ****** of all of them. He went to the toilet, tried to flush it, but it wouldn't flush. He noticed that the cistern lid was suspiciously ajar and lifted it to investigate. He quickly found the toilet roll tube, so he removed it. The ballcock went down, the tank filled up, he flushed the toilet and left. I'm certain that he would have been feeling quite pleased with himself that he'd caught on to one of the pathetic Saturday boys' little jokes so easily.
Little did he know.
Of course, once the ballcock went down it filled up with water so it stayed down. The cistern filled, and then it overflowed. Nobody discovered it until the water was flowing out of the gents, across the canteen, across the landing, and down the lift shaft into the warehouse.
I had to pop in a week later to pick up my last pay packet. The manager took me into his office and asked if I knew anything about the flooding that had occurred the previous Saturday evening. What flooding? So he told me. I really don't know to this day how I managed to keep a straight face.
some of these are hilarious
one i pulled was back at school (only a few years back, approx 2009), back when windows XP was the bee's knees. I wrote a simple batch script to run the shutdown command with a 10 minute timer, and another one disguised as autorun.inf (or something like that) on a usb drive, which would copy the aforementioned shutdown thing into the user's startup folder when the usb was inserted and autorun was ran automatically and straight away. plugged the usb into one of my friend's laptop and chaos ensured
the funniest part is that he continued to use the laptop whilst timing himself for the 10 minutes shutdown every time, and making do by turning the computer back on every time, instead of looking to get rid of it eventually we felt bad for him and because he couldnt really do his work, we deleted it from his startup folder
another variant was to open a webpage of a famous song by Rick Astley, also copied itself into the startup folder for good measure, and i think we had an offline version too but that takes a little while to copy over
dam you microsoft for patching this