This is an easy enough prank to recreate that is actually fun and very much harmless. Nobody and nothing gets hurt and in a few moment the person will understand it’s a prank so really no harm done. At the same time it’s a good way to let off some steam and laugh together (especially if you have active and bored kids who love breaking your stuff)
What you will need:
Your friend's/kid's/partner's computer PC/laptop (turned off, access not required)
Your phone's camera
Paint.net or other equivalent editing photo app of software.
The following image (or any other cracked screen image off the internet).
And here are the instructions of how to (almost) give your loved ones heart attack:
While they are away or asleep, take a straight photo of your loved one's open laptop. Make sure it's clear that it IS their laptop (include the surrounding of your room).
When they go to bed, hide their laptop.
Download the above (or similar) image of cracked screen.
Send the photo of your loved-one's PC to your own laptop to edit (or open an editing app on your phone)
Edit-in the cracked screen image to fit your lover's/partner's/kid's/parent's/friend's/yougetwhatimean laptop.
Send the finished edited photo to their phone with a text of "I told you - NEVER leave your stuff within kids' reach" (you can substitute "kids'" with "dogs" or "my").
Wait for them to wake up and check their phone, then frantically try to locate their precious PC. Tell them you put the PC away for fixing and give it to them when your inner evilness is satisfied or one step before they fall into coma.
Happy April Fool's Day!