Praxeus is an alien pathogen that targets plastic particles which, after arriving on Earth through interstellar means, became a fatal disease as it began infecting beings with plastic inside of them such as humans with trace amounts of microplastic and animals that consume plastic waste such as birds.Ther precise means by which Praxeus spreads remains ambiguous, but when contracted, one of the primary symptoms as a result of infection is dry, pale cracks running along the skin. These cracks can take anywhere between a couple of seconds to several minutes (at least for humans) before it completely covers the body. Once the body has been completely covered in said cracks, the body will then disintegrate into dust. Praxeus effect on birds is arguably less precise as they don't experience the same symptoms as humans infected with the pathogen and instead seem to be a means by which Praxeus can travel long distances to infect areas with a large populace. In an effort to prevent Praxeus to continue spreading, a cure was developed that was derived from bird enzymes.
The primary reason as to how Praxeus ended up on Earth was due to a group of a humanoid race of unknown species using Earth as a means to study Praxeus by using the human inhabitants as test subjects in order to find a cure after they were infected. despite their best efforts, they were all killed by the pathogen.
- (revived) Doctor Who Series 12 Episode 6 "Praxeus" (2020)