According to Freeman Dyson, in rather unimaginable 101500 years from now, and in case proton decay does not happen, most of nuclei will either fuse or decay into iron. This will leave the universe inhabited by “cold spheres of pure iron”. I think it is cool, even if I won’t live that long to see it. However, I came across a report of recent (2006) observation of ‘iron star’ with NASA's Spitzer Space Telescope. I don’t think these objects are the same as Dyson’s iron stars though, just the next best thing.