Many years ago, I had the original series of California raisin figures on my desk. I came in to work one morning and found that the guys on the night shift had kidnapped them. I had to follow an intricate wild-goose chase with clues placed all over the building to finally find them in the freezer compartment of the refrigerator in one of the break-rooms.
In the Telephone central office switch room we had large fireproof trash cans with heavy steal lids. One of the switch guys loved to drop that lid right behind someones chair to see how far they would jump. He would sometimes use a heavy metal pedestal from a relay rack install kit when the trashcan lid was not handy. One day a new manager was in the Switch room looking at a monitor screen and he could not resist pulling his infamous trick. She didn't appreciate it very much but surprisingly he is still employed to this day.
Also in the Eighties, one of the network engineers walked outside after a midnight shift to find his vintage citroen sitting on the loading dock. Several of the guys had done the seemingly impossible feat of picking it up and carrying it there.
Once some workmen had erected some scaffolding in our office area consisting of iron pipes and boards so they could work on something up above the dropped ceiling. Of course, they went away and left the scaffolding. After a few days of this, the boss came in and found that the entire scaffolding had been disassembled and moved into his office, with his desk right at the center of it.
I wasn’t involved with that one, but on another occasion, I felt the need for a retaliatory strike, so I rigged up a noisemaker that could be attached to the underside of a desk with magnets. It was pop riveted closed and activated by pulling out a pin (grenade style). The pin was linked to a chair with a piece of string. The best part was that if anyone tried to grab the thing, they got a harmless but painful electric shock.