You take a $0.25 coin, stick it in the middle of a coil of wire, and dump an tremendous amount of current through the wire all at once. The following sequence of events then happens in a tiny fraction of a second: the current very rapidly generates a magnetic field, in accordance with Ampere’s law. This rapidly increasing magnetic field generates an electric field, in accordance with Faraday’s law. This electric field generates a current in the coin. And this current itself produces a magnetic field. Lenz’s law dictates that this magnetic field will point in the opposite direction from the original field. These opposing field compress the coin into a much smaller distorted disc.
What’s especially snazzy about the particular instance in the link is that they’ve filmed it with high-speed cameras operating at a hundred thousand frames per second. It’s pretty amazing to see in action, though even at these high speeds the compression only takes a very few frames.
Trivia question: in the first video, an experimenter reminds everyone to look away before he pulls out the pin to discharge the remaining energy in the capacitor. Why?