the Lone Ranger Atomic Bomb ring, distributed by Kix cereal from 1947-1950 for 15 cents and a mail-in box top. it was a spinthariscope containing radioactive Polonium-210. you would take it into a pitch-black room, remove the tail cap from the 'bomb', and look through a tiny lens to see flashes of light from the Polonium-210 atoms decaying into Lead-206














