In Norse mythology, Mjolnir is the war hammer of Thor, the god of lightning, thunder, wind, rain, and oak trees. Mjolnir is the most feared weapon of the Norse gods. It was believed to be able to knock down giants and entire mountains with only one hit.
There are different stories about where the war hammer came from. One theory is that Odin had the weapon made in the heart of a supernova when Thor was born. Other stories say that it fell to Earth like a meteorite. Because of this, many Norse followers believed that lightning strikes were a sign of Mjolnir on Earth.
Mjolnir was the symbol of regeneration. It was not just about destruction.
When thrown, Thor's Hammer would return to his hand after hitting its target. It is said that Mjolnir was used by Thor to slay Jörmungandr during Ragnarök.
...He (Thor) would be able to strike as firmly as he wanted, whatever his aim, and the hammer would never fail, and if he threw it at something, it would never miss and never fly so far from his hand that it would not find its way back, and when he wanted, it would be so small that it could be carried inside his tunic.