This was not done as an Aprils fools prank (it was around the Christmas holidays likely over 20 years ago), but it could be used as an April fools prank.....
During the Christmas holidays when I visited my sister's house they had, among other snacks, a bowl of walnuts sitting out.
Well, I cracked them open by twisting the halves in different directions as it was less messy as I could open the walnut to have 2 halves instead of a bunch of small shell pieces from using a metal cracker.
I then realized that after eating the meat out of the walnut shell I could fit the two halves back together again and they would fit tight and hold together and look just like an untouched, unopened walnut.
First I thought to put empty walnuts back in the bowl as a prank for when the next person opened it and found nothing.
THEN I got an even better idea !
I took small sheets of paper and would write funny stuff on them and fold them up so they would fit inside the empty shell !
I may had thought of more, but two of the funny things I remember writing for people to read when they opened the walnut expecting to eat were -
"Help - I'm being held captive in a walnut factory !" and
"Sorry ! ......please try again !"
So I carefully put those empty note filled walnuts back in the walnut bowl.
I didn't hear any results that day so no one had got to them then, so the next time I saw my sister I wanted to see if anyone got a good laugh and asked her about them.
She said something like "I ended up taking those to work to set out for other employees to help themselves !"
So I guess some people on her job either got a good laugh or though there are some strange people around here and maybe gave her some strange looks
if they knew she brought them !