did a similar thing to an old bloke at work in our partitioned office. He was on the other side, we plugged a second mouse in and over the course of a few weeks we'd randomly start moving it or clicking. Short bursts, intermittently. The game was up when he heard 6 of us hiding behind the partition trying to stifle laughs as he swore at his broken computer....
Hiro you must just work for a boring engineering company... Superglung phone receivers to the phone, swapping keys on the old 2 finger typers keyboard, screwing peoples desk drawers shut, hiding peoples gear while they're on leave and leaving treasure hunt clues around, painting the inside of their safety glasses, all sorts of Dye marker shenanigans....
that's interesting, working in manufacturing in the past I'm going to say shopfloor guys are so full of shit and have such stupid chips on their shoulder it's not funny.