This paperclip isn't your ordinary paperclip. It's actually made out of something called Nitinol, aka nickel-titanium, aka shape-memory metal (SMA) aka Memory Metal. See, with SMAs (there are other alloys that have this property), you can deform them at one temperature then restore their original state with a different one. As you will observe in this video, the uploader bends it in cold temperature and makes the paperclip a paperclip again by putting it in hot water.
Very cool! Magicians use this material for magic tricks to hack spoons so the bend bend.
Watch The Nitinol Magic Now!
Nickel titanium, also known as nitinol, is a metal alloy of nickel and titanium, where the two elements are present in roughly equal atomic percentages e.g. Nitinol 55, Nitinol 60.
Nitinol alloys exhibit two closely related and unique properties: shape memory and superelasticity (also called pseudoelasticity). Shape memory is the ability of nitinol to undergo deformation at one temperature, then recover its original, undeformed shape upon heating above its "transformation temperature". Superelasticity occurs at a narrow temperature range just above its transformation temperature; in this case, no heating is necessary to cause the undeformed shape to recover, and the material exhibits enormous elasticity, some 10-30 times that of ordinary metal.
Learn More on Nitinol