I installed "cloud to butt" on my coworker's pc. It's a Chrome addon that changes all instances of the word "cloud" being displayed to "butt". He didn't notice for months. Last week he finally asked me what that customer could possibly mean by "uploading files to my butt".

I have hidden a tiny speaker in an adjacent cubicle wall that emits a soft cat meow every 2 hours.

I whistle Christmas songs in months other than December. Just the first few lines once or twice an hour. Give it a few hours and they're questioning why jingle bells is stuck in their head mid June.

Made a new folder on his desktop called Russian Dwarf Porn and then took a screenshot. Set the screenshot as his desktop background. For an engineer it took him a ridiculous amount of time before he realised why he couldn't delete the folder.

Found a little script a while back that would randomly open and close the disc drive on my coworker's computer. Not incredibly often, but enough to the point where it was annoying. He requested a new computer, I reinstalled the .scr as soon as he left that day.

Gradually increase the pressure required to open the office door by adjusting the automatic door-closer with a screwdriver so they become accustomed to giving it a mighty shove then one day disconnect the arm altogether.

Change their auto-correct settings in Outlook so when they type their name it adds a ridiculous title. Example: Tom Smith = His eloquence, master of ceremonial duck herding, and debater of microwave etiquette, Thomas "The Velvet Hammer" Smith, Esq.

There was this girl sitting next to me in an open plan office and we were always joking with each other. One day, she had a meeting scheduled at her desk with a male coworker I knew she had a crush on. So while she was in the bathroom getting ready, I went on her PC, found the guy's photo on the company website and made it her desktop background. Then I tabbed back to whatever programme she had been using so she wouldn't notice right away. She comes back. Guy arrives for the meeting. They're talking away for about ten minutes before she goes to check something on the computer and just let an enormous shriek out of her and goes bright red when she sees the desktop. In a way, that prank almost worked too well. Because her shock was so obviously genuine, it was obvious she was the victim of a prank (rather than a crazy stalker, which is what I was aiming for.)

I plant evil questions in their lectures and tutorials, seeding them to students we have in common. I've been doing it for years, and they have no idea it's happening. They're just constantly baffled that the same kids each year keep asking obscure, graduate-level, often borderline unanswerable questions in person, but never quite manage that level of insight in their writing.

I just keep handing them random items. 99% of the time they'll keep accepting. Or I'll stare at a spot slightly above their eye, like they have a booger on their face or something. Or I'll slowly back up as we talk, see how far I can get them to follow me before they catch on.

On a windows machine, go into the mouse settings and enable "Click Lock". This changes a primary button click into a toggle on/off instead of the standard press and release for highlighting and click and drag operations. It's infuriating as hell and obscure enough that most people assume the mouse is broken and will request a new one. The new one will do it too. Or just microwave some fish.

This is only to my bosses, but when I know I'm due for a raise/promotion and they tell me they don't have budget/I need to wait a while, I start wearing suits to work. Not everyday, but maybe once a week, maybe twice, skip a few, repeat. Looks like you're going to interviews during lunch or after work.

Grabbed a roll of stickers from the pharmacy that say "For rectal use only" and randomly attach them to pens, phones, staplers, the water cooler. It's all good till our director comes in and loses his shit and can't help but laugh.

I'm a 28 year old dude and I used to put up one new kitten photograph in my cubicle per week to see if any of my managers would say anything. After putting up enough pictures to cover my whole cube wall, and no one commenting, I started to feel like I was going crazy. I guess the joke was on me, or else all my managers were just super accepting.

think I've mentioned this before, but I have a few co-workers (myself included) that run on post-it notes. Seriously, some of our desks look like that Pepe Silva scene in Always Sunny. That said, I take advantage of this. I do fairly well at copying other's handwriting. I'll do my best facsimile of something innocuous or mildly ominous and place it among their other post-its. My notable favorites were: "Ask Linda about the bees." and "Knife Parade?"