HOWTO make a disappearing prank gallium teaspoon

Disappearing Spoons sells kits to make your own gallium prank-teaspoons. Gallium spoons weigh nearly as much as stainless steel ones, and have a similar finish, but they dissolve in hot liquids like tea. When the tea cools, the gallium forms a lump in the cup, ready to be molded into a new prank-spoon!

Disappearing Spoons (via Make)