Eye popper
An eye popper, also called hopper popper, is a popular children's toy.
An eye popper is a small, dome-shaped piece of rubber or similar material resembling a half of a rubber ball; the shape of a smile is often imprinted on the dome. When pressed, the toy inverts, but after a few seconds, it pops back into its original shape, making a loud popping sound. If resting on the ground when this happens, the toy will fly several feet into the air. The eye popper's behavior resembles the process by which a ball compresses upon hitting a hard surface.