The Slime
Xanthoncos spitzbergensis
Water
Sexual
Monoecious
Amorphous
Yellow
The Slime (Xanthoncos spitzbergensis), also known as the Spitsbergen slime, is an extraterrestrial slime mold responsible for causing yellow lung on humans. A parasite, it lodges inside the respiratory system and gradually replaces the host's organic tissue until they die. The corpse is then reanimated for an efficient dispersion of spores to healthy humans. If approached, it will attack, whether through screams, scratches, or bites.
The Slime arrived on Earth in the late Pleistocene. It was buried in the permafrost of Spitsbergen for thousands of years, the first ever transmission only occurring in the 1940s. After infecting the entire Svalbard archipelago, it spread to Britain, Norway, and the Soviet Union. The German administration of Norway sent samples of the Slime to the Reich proper in order to be experimented on, but they broke free, contaminating North Africa and even more parts of Europe. Most of the continent had fallen to the pathogen by 1945, at the cost of over ten million lives.