When I worked for Disney someone sent me these to try out on my daughter. She was about three. They were fantastic. It’s a little tattoo with a pen and you write in a phone number. So it’s like adding a little “if lost please return to” tag like you put in your wallet or book. Now you can do it for your kid. Brilliant. And they’re fun. Only problem is if you lose the pen. Check it out. Here’s the website.