There is also Superman’s key. Made of neutronium.
https://dcmovies.fandom.com/wiki/Fortress_Key_(All-Star_Supe...
Last I tried to calculate (poorly), if you were to touch it. You liquify and be sucked into it just before contact.
https://dcmovies.fandom.com/wiki/Fortress_Key_(All-Star_Supe...
Last I tried to calculate (poorly), if you were to touch it. You liquify and be sucked into it just before contact.
Assuming "dwarf star material" means "neutronium" (which is unstable at any level less than a neutron star) and the "half million tons" mass quote for the key…
That's about the energy content of all the world's fossil fuel reserves being released in a 10 minute half-life.