So this literally just poped up in my head so its not exactly fleshed out…
Ok so we got diseases and we got infections so why not parasites? For instance eating a piece of raw (or cooked but with a much lower change) meat may give you a tape worm that makes you take less nutrients from food. There could even be mutant versions! A mutant tapeworm could completle negate any nutrients you get and ,basically, starve you to death.
Of course there could be the other side too, symbiots. For instance some form of plant organism that lives on your skin and provides you with sustenance or slowly heals you, when in direct sunlight. You would ,of course, have to take care of it as well.
It could have a change to be hurt in melee combat or die if it dosent get any sunlight for a few days!
Technically you already have a symbiotic relationship with this odd organism! Its pretty much ignored from a game play perspective, and is just there to hand-wave your magical health regenerating sleep and mutations. It will be elaborated upon and expanded sometime in the future, but that is possibly very far off from now.
Oh well now that I think about it, wouldn’t your odd organism be able to drive out other common parasites?
If you wanted to have some kind of mutant tapeworm affecting you, what makes it so mutated anyways?
I don’t understand what makes GIANT spiders GIANT :I