Yes, it can be used to form a Dodecahedron.
I don't see how! But cut out a pentagon from a piece of paper. Next make a fold along a line between any 2 corners which are not next to each other. It's no longer 2D.
I am not sure what the second sentence is about, but each of the 12 faces of a Dodecahedron is a regular Pentagon.
You can also make a pentagonal prism, of course: two pentagonal ends joined by square or rectangular sides. (This is the basis of the prism in the viewfinder of a single-lens reflex - or SLR - camera.)