What does unobtainium do in stick RPG 2?

Answer 1

It is used to upgrade your sledge hammer at the laundromat at the first island,

but that is the second upgrade, this is how you get the first:

you buy toilet paper from wally mart and then you give to the guy in the boys bathroom of the bar. and he gives you the sledge hammer.

and to buy it you have to go behind the building near the first island exit at night, then he shows up with a bunch of items