There's a metal that "remembers" its original shape and snaps back to it on its own

Shape-memory alloys like nitinol (a nickel-titanium alloy) can be bent, flattened, or twisted into almost any shape by hand — and it looks like permanent damage, the same as it would with an ordinary piece of wire.

But heat that metal to the right temperature (sometimes just body heat or hot water is enough), and the object spontaneously "remembers" its original shape and springs back to it, as if it had never been deformed at all.

The mechanism has nothing to do with magic — it comes down to a phase transition in the metal's crystal structure, switching between two stable atomic arrangements, triggered by temperature.

These alloys have real medical and engineering uses: from self-expanding vascular stents, to eyeglass frames that spring back into shape after being crushed, to structural components in aerospace.