Office prank #2: "I hear voices"
"Do you hear something?" "No, I don't hear anything." "You sure?" "Yeah, I'm sure." Liar! You hear something—a radio playing. And you know you hear it because you're the one who set this trick up! This is the best office prank for people who believe in ghosts. And here's how to do it:
1) Find a small radio, set it to a station guaranteed to piss off any sane person, then put the volume on low.
2) Remove a ceiling tile from above your victim's desk.
3) Hide the radio inside, then replace the tile.
4) Keep denying that you hear any noise. "No, I still don't hear anything. You sure you're okay?"
Office prank #3: This is the best water ever!
Here's one of the best office pranks everyone will happily fall for. Replace the water in the water cooler with wine. All you have to do is take an empty water canister, pour in the vino, and put it back on the cooler. If your coworkers are teetotalers, try tonic water. This funny office prank will secure your title of 'life of the party'! These ridiculous office rules will make you glad to work where you do.
Office prank #4: Sound the horns!
With most office April Fools' pranks, you have to hover nearby to know when someone's been victimized. But with air horns, you can be anywhere and you'll definitely know when someone's been punked. This is the best office prank for offices that are always quiet. It's also the perfect trick to pull on someone who has the office that should have been yours: Remove the office door bumper. Replace it with an airhorn. Make sure the airhorn knob is situated where the door will hit it. Shut the door, ensuring your victim will open it. Cover your ears when you spot your victim about to throw open his or her door.
The Best April Fools' Day Office Pranks Anyone Can Pull Off, Source:https://www.rd.com/funny-stuff/april-fools-office-pranks/