One of the settings for a story I'm writing is gigantic worm-like animal. Being so large it stands to reason that there would be comparatively smaller animals living within and on the surface of it. Would it then be possible for these smaller animals to also have even smaller animals living on and in them, going all the way down like a russian nesting doll set of parasites?
EDIT: I didn't include it in my original question because I wanted the answers to be as rooted in biology as possible, but the giant worm in this scenario subsists by devouring other alternate universes/realities. The creatures living within and on it range from the same variety of eaters of "intangible substance" as it is, and others that eat flesh and blood in the same way animals in our reality do - along the way this intangible food source is gradually turned into something these other creatures can feed upon. So as admittedly ridiculous as it sounds, this ecosystem does have an input source of energy.
