[Cerium]

I knew a guy that made a lightsaber that only he could use. Part of the act was that only a "real Jedi" can activate a lightsaber. He used a neodymium ring and a hall sensor. The trick was seamless.

[HeyLaughingBoy]

With all the people getting magnets implanted subcutaneously, that would be an even better trick!

[sslayer]

This would end badly - around this Thors hammer, it would rip them right out through the skin.

[curiousGambler]

And this is why I will never get a magnet implant, despite the wicked cool ability to sense active AC power lines.

[tsotha]

As would an MRI, presumably.

[spike021]

What about implanting an NFC chip and having the hammer stuck to a holder/floor as-is with a strong magnet?