Demon core

then then if that's happening at a rate that sustains itself uh it'd be a critical state now if the chain grows at a steady rate then that's a critical mass but if you go a step beyond that now i am quoting to say that the rate of the nuclear chain's growth is accelerating over time not remaining steady then this is a supercritical mass and is capable of creating spontaneous fission which can exert a fatal amount of energy.

See the infamous Demon Core for a terrifying example.

And I think this happens in, isn't there a Manhattan Project movie or something? What's the one with John Cusack in it? Doesn't he get killed by the Demon Core in some movie about the Manhattan Project? I think that's right.

Yeah, Jack Black kills him with a supercritical demon core, which is what's a filing of a type of music in a music store.

And so, yeah, now this, what? What does it mean in the context of our attempt at a narrative?

Well, when something's super heavy, it will lead to a rapid alpha decay most times.