The [Xeelee](https://en.m.wikipedia.org/wiki/Xeelee_Sequence) stories involve [photino birds](http://spacebattles-factions-database.wikia.com/wiki/Photino_Birds) which are dark matter life forms that use dense normal matter (inside stars) to reproduce by a 3D templating process.  They are making stars turn red and "old" in a few tens of millions of years, not the expected billions.