This is a cowrie. I found it while I was walking on the beach last night. It’s dead. Weeble.
But when cowries are alive, they’re amazing animals. They eat sponges (cool) and cruise slowly around on the reef looking all glam and sparkly. They stay sparkly because they have a crazy long foot (just one) that they obsessively rub over their shell to remove little creatures that want to hitch a ride. A very slow ride.
They’re beautiful. Just remember that if you find one, as with all shells, don’t take it unless it’s dead.