Tired Mom's Prank Gone Wrong

I decided to prank my kids by hiding their favorite toys and leaving clues around the house. I was tired of hearing 'Mom, where's my [toy]?'. But then, they got too excited, found everything quickly, and started crying because the game wasn't challenging enough for them. Now, we're all just tired and sad. Did anyone else try a prank that backfired like this? How do you handle cranky kids looking for their toys?