This prank is one to build up to April Fools Day. Every time you are near someone leave pennies / small coins without them noticing.
Leave a ton of pennies everywhere. If you know where they work, wait till they go out for lunch. Throw a few pennies on the floor of their office. Slip a few into their coat. If they leave the window on their car cracked, shove a few pennies inside it.
If you are ever in their house, leave pennies in really weird places so that they will be discovered eventually. Pennies in the fridge. Pennies inside of their socks. If you can do it sneakily enough, put pennies into their pockets.
But never let them find out it's you.
More April Fool Pranks
Aprils Fools' Day prank: Ripped pants. When you are near your mom, drop the pen to the ground. As you reach down to grab it, it seem you rip your pants.
The One Day Catfish
This joke is for your friends with a really good sense of humor. See if you can catch them in your trap of love and lies.
Send An "Accidental" Text Message
Pick a 'needs to know it all' friend from your group, and send a text about a juicy secret.