“The Deathworlders” is a shared fiction based on the premise that Earth is an unusually dangerous place, and anything that can survive there is also unusually dangerous.
I first heard of the idea through Reddit and Tumblr comment threads posted via the aggregator site MediaChomp. But I was able to track it down to its original archive.
The Deathworlders is now a major story with at least 90 chapters. I am currently somewhere near Chapter 67. Here’s the beginning, which was originally posted as a stand-alone story:
The Kevin Jenkins Experience.
More info:
https://www.facebook.com/HamboneHFY
https://deathworlders.com/books/deathworlders/