I used to have a colleague who would generate top banter by turning on the high contrast theme, Windows narration, etc.
He did it to me, though, and ended up rebooting my machine - I'd been fixing a bug in the patient records system (NHS) so I was not best pleased. He evidently didn't have enough password resets to keep him busy.
Thank god for c$. I created many embarrassing files with lurid titles like 'senior manager on toilet.mpg' changed the permissions on them to exclude him.
He found it funny, then a bit exasperating when he realised he couldn't delete anything, choosing to no-sell the issue, until - being a Friday - he had some issue with the timesheet program and the very comely lass from HR jumped on his machine to do a quick fix with his timesheet thingy.
She ended up ringing him to tell him to stop fighting with the mouse. I looked over and he was white as a sheet.
After she'd sorted his issue, I did cop to being the culprit. I felt a bit bad, lest it all escalate and mine was potentially more vindictive, us and jg colleague's names.
I explained I was happy being pranked but I always retaliate and lack any sense of where a line is drawn. There was a perfect understanding then.
I did chuckle as he described the cursor the lovely HR lass was controlling, first minimising his windows, then gliding across his desktop... Visibly pausing as it hovered near some extremely suspect 'videos'... And she finished her little tinker in record time too!
Productivity was much higher that Friday afternoon which was a bloody first