Best prank?

Buddy from high school and college days was planning a hiking trip through the Superstition Mountains looking for the Lost Dutchman mine. Legend has it that it is haunted and bad things happen to those who do so. So a bunch of us organized a campaign to have his mail box flooded with warnings. The trick was to get them sent from places having no obvious links to any of us or anyone he knew. I think I won. A former employee of mine had returned to England and was working for the London Times covering Parliament. So my buddy got a warning postmarked from inside Parliament itself.

Best one I've heard of was played by work colleagues on a guy who'd bought a new hat. They went to the store, bought the two of same hat, one size up and one size down then kept furtively swapping them around.

And guy I worked beside brought a hard boiled egg to work every day for lunch, and cracked it against the radiator. One day somebody (!) secrety swapped it for a raw egg.

@Really not a prank as such rang our boss up and played him something relevant about him banging on about something all the time .. i was killing myself as we 0layed it over the phone our boss never said anything about it but would of no doubt had his suspicions who was behind it

Long story, but the end of it was me using a forklift to dump a Conex container full of Styrofoam packing peanuts into a Mustang convertible... filled it up!

I took a much-deserved bow after that one.,

I was working nigh shift, andd do the two of us went to the park and waited in the dark for one of the workers and grab her, for some reason she was pissed off screaming like a b!tch