The Nemesis Fungus

The Nemesis Fungus (Astergeniscea Collema Nemesi) is the eponymous psychic parasitical fungus originating from the planet of the same name in the Oort Cloud with uncanny resemblance to jelly lichen fungi. Its goals are the subjugation of humanity and trans-galactic conquest.

Origin
Planet Nemesis once orbited the Sun on the opposite side from the Earth. It was here the Fungus evolved from. Gravitational interaction with Theia before its collision with Earth nudged Nemesis out of alignment, eventually placing Nemesis under the strong influence of Jupiter. Jupiter slungshot Nemesis out past the Heliosphere to rest in the Oort Cloud. By the time the Fungus was able to leave Nemesis's gravitational influence, the only option for reaching the inner Solar System was by hitching a ride on a comet. It did so on Halley's Comet, before the same force that ejected Nemesis from the Solar System thrust the comet into a short period with Mars. Thus did the Nemesis Fungus return from icy exile to conquer the inner solar system.

Martian Infection
see: The History of Mars

Mars once was home to a flourishing tripedal race far in advance of modern humanity. An introspective race, the Martians never bothered to leave their planet, a choice which ultimately led to their undoing. The Martians' highly developed psychic senses proved to be a perfect transmission vector for the Nemesis Fungus, and the race species was quickly and completely infected. Ravenous from years without a source of psychic energy, the Nemesis consumed the Martians whole, physically and mentally. The Fungus, now fat with parasitized psychic energy, then went back into hibernation on Halley's Comet to wait for the proper alignment of planets to shift the heavenly body's orbit to pass by Earth. Using the comet as something of a staging ground, periodic bombardment by meteoroids originating from the comet serves as a means of travel to Earth, and in 1998 BCE, one such meteoroid impacted in Egypt's Middle Kingdom, the priests of which quickly were subsumed to the will of the Nemesis and groomed into becoming the beginnings of the Cult of Ibis.

Intentional Infection and Hybridization
The Cult of Ibis in their infinite stupidity has found ways to harness the Nemesis Fungus to genetically enhance humans. The process of combining genetic data with the fungus allows for capabilities beyond that of a non-fungal human, though of course at the cost of your humanity. In ages past this was done with an special elixer containing the fungus, but in these modern times the Cult has perfected the science of fungal hybridization with the creation of Genetically Otherized Thetahumans

Infection Process
see: Encephalomycotoxicology and Encephalomycological Propagation Mechanisms

Prevention and Treatment
see: Evading and Combating the Nemesis Fungus