Rainbow Worm Species in Yonderverse | World Anvil

Rainbow Worm

Fear the rainbow worms, for if you don't, you will be their dinner. Do not anger them, or else they shall destroy everything that you love.
Mark my words, do not get on the bad side of one.
— Some mysterious person
Rainbow worms are the apexiest of apex predators on Osao. They are ever-growing, ever-eating animals that roam the entire planet. Be wary, as they are incredibly dangerous and can destroy towns and cities with ease.


As bright and colourful as these animals are, do not touch them. Their incredibly sharp scales are laced with the most toxic poison on the planet, and if even a smidge gets on your skin you will die in just a few minutes. These rainbow scales are present along the entirety of their two hundred feet long bodies as babies, and up to four thousand feet long as adults.

Rainbow worms have heads the same size as their bodies, with large mouths. Their orange jaws are lined with incredibly sharp teeth, which have merged with a rim around their jaws to form what looks like a pair of lips. Their eyes are large and glassy, with smoke-like patterns wriggling and writhing inside.


Rainbow worms will literally eat anything. If they can't find enough live food, they will resort to consuming the ground itself. While they already consume soil and rock, they usually expel it but in times of scarce food, they will absorb some of the rock into their system. This can be problematic, since when lots of the worms do this in a specific area, the ground becomes unstable, resulting in earthquakes, tremors, and an assortment of other disasters.

Larger rainbow worms have been known to consume entire settlements in just a few bites. The worms typically just swallow what they can and continue on their paths to find more food, but when a large supply is present in a small area, they will circle it and consume it in its entirety. This was the case for the Great Swallowing of Slimetown, a small desert town in Unuth where the largest rainbow worm ever recorded swallowed Slimetown in one bite.

Luckily, since rainbow worms live so deep down underground, they don't often appear at the surface. They usually hunt other rainbow worms and burrowing animals, of which there are an extraordinary amount, but when this food runs dry they dig up to the surface in search of more food. If there is a lack of food here, only then will they absorb the very soil of Osao.


The reproduction of rainbow slimes isn't really known, as these animals live very far underground and people generally don't want to get close enough to study them. It is theorised that rainbow worms undergo asexual reproduction, producing several identical worms that immediately disperse and live on their own. Most animals are good parents on Osao, but the fact that rainbow worms have never been spotted with young nearby leads scientists to suspect that they don't tend to their children at all.


Thankfully, rainbow worms inhabit the lowest depths of the planet's crust. They spend their entire lives consuming other burrowing animals, occasionally dipping into the liquid mantle to prey on some magma-swimming monsters. Despite this, they are sometimes seen on the surface of the planet, to hunt down creatures when the supply in the depths runs now.
1000 years
Average Length
4,000 feet
Geographic Distribution

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Author's Notes

Thank you Qurilion for the idea!

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