Welcome to Make It Magic!
A puzzling penetration.
The magician places a coin into a small round box. The coin fills the interior of the box. Yet the magician is able to penetrate the box with eight solid spikes - creating a "spiked" coin.
The nails are removed from the box (by the spectator, if you like) and the coin is shown unharmed. All may be examined at any point during the effect.
Easy to do - no sleight of hand or difficult moves to complicate the working.
A real half dollar may be used also!