Metal X

 is an alien metal found on Mars. Among the unusual properties of Metal X is the ability to completely negate gravity allowing a person wearing an object, such as a belt, made of Metal X to fly. It has many other properties that have yet to be revealed in full. It is hyper-conductive and is able to invert and alter the state of mesons and gravitons.

When in physical contact for a long time, it can and will accelerate the healing factor of the wielder. It's more durable than steel but lighter than titanium. Once, Ryūken Senju used a net made of metal X to trap Shinzui Uchiha who was trying to escape using Kamui. Thereby, he came to the conclusion that, Metal X negates dimensional shifting that an Uchiha would be capable of.

The name of the discoverer of Metal X on Earth has yet to be revealed but Ryūken was the one to put the metal to practical use.