EDIT: There are NO spoilers ahead for any book.
So i have an idea: is it possible to create a black hole using the Feruchemical ability to store weight?
First of all i am no physicist, and all my calculation my be incorrect, so feedback is appreciated.
storing weight in iron is something a feruchemist do all the time and it's said that it changes his density when tapping the iron - not his strength though it affects it.
and what is a black hole if not a really REALLY dense point in space?
Could a skimmer store enough weight to use it all in one second and make himself so dense that even the light can't escape his gravitational force?
there are standards to black holes - according to wikipedia - some are huge, some are even micro.
Assuming a skimmer who is 1.80 meters and 80kg, is storing 99% of his weight, we could, after a bit more than a whopping quadrillion years (1,000,000,000,000,000) use all that weight in a second to make himself dense as a large black hole.
But we don't really need a whole second isn't it? we can do it in half a second' or a tenth, or a planck second: the shortest time possible in the universe.
This actually shortens the storing time to less than a second!
That's not even considering compounding...
Sanderson once said that increasing weight affects the Higgs field, which is essentially gravity.
The only problem I see is that they will need to empty the reserves in the shortest time possible according to science,
and by what i have read i don't see any indication to the speed of which you can tap into a metalmind.
In conclusion, any skimmer can destroy Scadrial without breaking a sweat.
If you want more calculations, or see something wrong please say so.
Thank you for coming to my ted talk.
TLDR; skimmer OP must nerf quick.