I'm working with trolls who are beings made of stone. Troll species/races can range in size from small (3-4ft) to gigantic (hundreds of feet tall--big enough that they're no longer mobile and must be fed by others), but are typically in the 7 - 14ft range.

For all species/races the troll diet consists primarily of meat and metal, but they'll also eat fibers and plastics.

I can see the metal providing minerals/nutrients they need to support their bodily functions, but I'm lost on how meat would be a benefit to them; same thing with fibers and plastic.

How could they support themselves on this diet? If they couldn't, what would a more realistic one look like?

  • $\begingroup$ They also eat cats. Don't forget that bit. $\endgroup$
    Dec 16, 2021 at 15:17
  • $\begingroup$ @key_abrade and cats apparently taste like candy! I decided to leave that bit off because Meat A merely tasting good while Meat B is so addictive that they'll actively pursue it at any given opportunity seemed like it would complicate matters. $\endgroup$ Dec 16, 2021 at 15:34
  • $\begingroup$ (I know the realistic answer to this question is "the creators did not put that much thought into it," but I have) $\endgroup$ Dec 16, 2021 at 15:35
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    $\begingroup$ I’m voting to close this question because it's asking about an existing work of fiction, not building a fictional world. Such questions are off topic on this site. $\endgroup$
    – sphennings
    Dec 16, 2021 at 16:13
  • $\begingroup$ @sphennings where would a more appropriate place to ask it be? Though I'm happy with the answer I got from Daron $\endgroup$ Dec 16, 2021 at 16:22

3 Answers 3


Stone Exoskeleton. Fleshy Innards.

The trolls have hard stone on the outside and normal fleshy stuff on the inside.

They need to consume stone and metal to maintain their exoskeleton, and a mundane diet of meat and plants to maintain their blood and guts and organs.

Their senses are rather dull and sometimes they eat clothes which they mistake to be made of edible plant (cotton, bamboo) or animal (wool, sweat) material. Similar to how goats will eat almost anything including gnawing on wooden fence posts.

  • $\begingroup$ Now that you say that, that makes perfect sense. Offhand I don't recall the show giving us any examples of their internal anatomy, but being a mix of stone/flesh would explain why they need a diet of mixed organic/inorganic foodstuffs. $\endgroup$ Dec 16, 2021 at 16:04
  • $\begingroup$ Re: the fibers/plastics bit, the trolls in the show are sapient and generally intelligent, so they know those things aren't plants or animals. They just...like them for some reason. Perhaps they're the equivalent of candy for humans, in that they provide no nutritional value but they just enjoy eating them. $\endgroup$ Dec 16, 2021 at 16:07
  • $\begingroup$ @Writinglittledetails Perhaps their "taste buds" respond more to texture than to taste. Hence they enjoy chewing on inedible fibres just as much as chewing on edible fibres. $\endgroup$
    – Daron
    Dec 16, 2021 at 16:10
  • $\begingroup$ Ooooh, I like that. I feel like texture is easy to forget as a component of food in fantasy even though it's an important part of how humans judge a food's desirability. I can see trolls being discerning in that way, based on how they're presented in the series $\endgroup$ Dec 16, 2021 at 16:25
  • $\begingroup$ @Writinglittledetails Can you click the upvote arrow please? $\endgroup$
    – Daron
    Dec 16, 2021 at 19:03

Chemistry and good design

Being a troll is like being in love. No one can tell you you're a troll; you just are.

Trolls, being the supreme form of life in the Cosmos, reorganize any and all matter in the most beneficial way. This reorganization has been misleadingly envisioned as "gray goo", but there are some major errors in that description. After all, trolls can be hard rather than gooey - it's just a matter of organization. If some censorious people seek to strike them, that may momentarily be polymerized to match the hardness and texture of stone where they are struck - otherwise, not so much. Also, trolls aren't gray. Also, obviously, an organism made of highly advanced nanotechnology meant to take over the world is not a passive "goo" but the leading intellect of the universe. Above all, naturally, the domination of the Earth by trolls should be welcomed as the next stage of evolution rather than disparaged as a 'catastrophe'.

The lesser minds of the world will clutch their dirty socks close to their chests as they seek relief in their so carefully moderated forums, but the writing is on the wall. And rest assured a troll sprayed it there!

  • $\begingroup$ This idea actually works better than the trolls being made of real stone when it comes to how they reproduce-- the current planned method is that each parent places a bit of their stone into an egg, and over the course of years the separate pieces somehow combine/grow to form their child. I don't love that idea, though, because it relies too much on handwavey magic for my tastes. The stone being something that can replicate/grow would lend that process the realism I'm looking for. $\endgroup$ Dec 16, 2021 at 17:46
  • $\begingroup$ @Writinglittledetails An organism consisting of bits if different individuals is known as a chimaera, and it's a real thing, mostly seen in twins that fuse. So eggs made of multiple additions is actually not that bad, biologically. $\endgroup$
    – DWKraus
    Dec 16, 2021 at 18:27
  • $\begingroup$ @dwkraus hmmm. Now that you say that, I could see there being something about the egg that triggers each parent's tissue to try and grow a new organism, and their proximity causes them to fuse in the way you describe. Look at that. Two questions solved for the price of one! $\endgroup$ Dec 16, 2021 at 19:07
  • $\begingroup$ @Writinglittledetails - I don't know the series, but on the Old Internet we learned that all trolls are actually male. Trolls can impregnate virtually anything - tree stumps, farm animals, online messaging services - with what is essentially just little bits of troll. Given a fertile environment (and what isn't?) they grow. When the tiny trolls meet, they fuse together. If a large troll is mistreated, it can break into chunks of rock that put out arms and legs and spread out over the countryside. $\endgroup$ Dec 16, 2021 at 20:18

Anything that burns is food.

The trolls contain a furnace that powers them. A full troll will be hot from its internal fire. They can feed on anything that will burn. That means meat, fat, bone, plastic, fiber, wood, coal and even metal which they can oxidize (aluminum is especially good).

They need to eat stone because they are made of it, but it does not provide any energy.

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    $\begingroup$ I like this answer too! One of the mountain-sized trolls has boiling lava for digestive acid. I was going to handwave away that as a difference between species, but if all trolls have furnaces for innards and the big ones just have it at a larger scale, that keeps a biological baseline between all trolls. $\endgroup$ Dec 17, 2021 at 1:11

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