What's the meanest/funniest thing you've ever done to a coworker?

One of our security guys came walking through the kitchen one day and I put a sign on his back that said, "Kick Me, I'm Security".

About an hour later I got a sharp slap on the arm and when I asked him what the hell he did that for he threw the sign on the desk in front of me. Seems he walked through the lobby with it on his back.

Whoops.

Before I went vegan I took several crab claws and poked them through a rubber glove. I took a lemon wedge and put it in my mouth. I had an accomplice turn the lights down in the restaurant and went in behind my friend, Robert. When the lights came back up he saw me standing there in a very Freddy Krueger kind of way and screamed like a little girl much to the delight of his fellow workers.

Clear Karo syrup works well also.:evilgrin:

From my hands to my seat...

But I put them right underneath the slots that rest the seat on the bowl. I carefully set the packets under there, so that when my coworker plopped his ass on the seat, the packets exploded, getting ketchup all over him. (This was at a college job in a warehouse, so I didn't ruin any nice clothes, but I did get yelled at by the supervisor, who luckily didn't know about the forklift race we'd had 20 minutes before that when the full time staff had a meeting.)

I also once created and installed a program that counted down from 10 on startup with the message that total system failure was imminent.

The only time I've heard that is referring to a candy or an actual ball of fire.

an actual ball of fire and a mouse ? lol

Thought maybe the term applied to something else as well.

Around about the time the first computer viruses were making the news I brought in a Macintosh to do some graphics arts stuff and taught a co-worker how to use it. While he had stepped out of the office for a minute, I turned on the "bugs" desk accessory. It causes little beetles to crawl over the screen. When he came back to his desk, he called me over to show it to me, so I announced that he must have caught a virus. He told others and soon the office was crammed with people wanting to see it. Eventually another co-worker exposed my hoax and I assumed things had settled down.

Apparently not.

That night, on the news, the lead article was about computer viruses and it was mentioned that such-and-such office (mine) had been affected. Then they showed a picture of a Macintosh running the "bugs" desk accessory (just a reminder, it's NOT a virus). On the 11 p.m. news they mentioned that the graphic on the 6 p.m. news was incorrect.

I have no idea if they got hoaxed separately, or somebody phoned my hoax in and somebody else ran with it or if the world just collectively lost its mind that day.

Ain't I a stinker? :evilgrin:

Photocopied my hand giving "the finger", and left it in random stacks of paper throughout the office.

Linking paperclips together whenever someone had a paperclip storage thingy on their desk.

Telling green interns that their ID doesn't work because I have no knowledge of their employment.

(I love fucking with interns and co-ops)

Phonying up a "Persona non grata" sheet for somebody(that was a masterwork), sent to me from Security.

that said "I LOVE GAY PORN". He was taking a trip from Minnesota to Florida, and didn't find it until I told him it was there, many many miles into his trip.