I bought a bottle of OPI Black Shatter nail polish. It's so cool! First you paint your nails any color you want. Wait for it to dry. And then you brush on one coat of Black Shatter. And as it dries, it does this:



The black crackles and shatters, and whatever color you used as a base shows through. Add a clear top coat to make it shiny, and it's done. This is my new favorite thing! :D