Immunity Challenge 11: Survival of the Fittest

The Atoz (IPA: /ˈei.tuˌzi/) is a rare creature with reptilian characteristics. It is known for its unusual combination of autotomy, parasitism, and mind-affecting toxins.

In many ways the Atoz resembles the more common Monitor Lizards, having the same basic body shape and general size; an adult typically reaches a length of about one foot from the nose to the beginning of their tail. Their tail is disproportionately long and thick in comparison to their body, due to its unique role (see later). Scales cover their body, but are quite weak and offer little protection. Their claws are not especially long or sharp, but their toes have the ability to strongly grip, allowing them to cling to other animals for safety. Their senses are generally poorly developed with the exception of hearing, which is very acute. Unlike true non-avian reptiles, the Atoz are warm-blooded, therefore allowing them to both survive in cooler climates or hide in dark areas when threatened.

What makes the adult Atoz unique is their method of feeding. Unlike their young, the adults do not hunt for their own food. Instead, they seek out a larger, stronger predator. What this predator is depends on the habitat of the Atoz; it may be a tiger in one area, or a bird of prey in another. Once a suitable predator has been located, the Atoz reveals itself to them and snaps off its tail. Some lizards do this to distract predators, but the Atoz has weaponized this. The Atoz naturally produces a strong mind-affecting poison, which is most powerfully concentrated in their tail. Once the unsuspecting predator eats it, the poison enters their bloodstream nearly immediately. The effect of the poison are similar to a more dramatic version of Oxytocin in humans: the animal begins to feel a strong bond of affection with the first creature it sees, which in almost all cases is the still-present Atoz. From that point on, the predator serves as the protector and provider for the Atoz. Larger animals are clung to, and when a kill is made the Atoz takes a portion of the meat. For smaller predators, the Atoz plays the role of their host's young, staying in a safe location while the host brings back food. Atoz poison does not affect the system forever, but the creatures are blessed with remarkable regenerative ability - given an adequate supply of food, their tails can be regrown within a week.

Adult Atoz are generally solitary creatures aside from their contacts with hosts. Mating occurs at a given time each year. To compensate for their rare meetings, Atoz are hermaphroditic. They abandon their current hosts to go towards a nearby Atoz giving off a mating cry. Once two Atoz meet, they wrestle for a while to test each others' strength. If their strengths are comparable, they proceed to mate, fertilizing each other. If one Atoz is much stronger than the other, the weaker one is rejected and excluded from the gene pool. Once mating is completed, the Atoz return to their old hosts or seek new ones if their previous one cannot be found.

Gestation takes only a couple months. Unlike true reptiles, Atoz give live birth to a small number of young, typically three or four. Because they rely on powerful predators, which are fewer in number than weaker animals, these small litters help prevent overpopulation. The baby Atoz are independent and typically scatter within hours of their birth. Before reaching maturity, they behave much like a typical small lizard, eating small insects that can't fight back and fleeing from predators, taking advantage of their warm-bloodedness to hide in the dark as needed.

Human contact to date with Atoz has been limited. There has been much interest in the function of their poison, with research being done about the possibility of its use treating anxiety and feelings of alienation. Ethical concerns have been raised concerning the idea of using Atoz poison as a 'love potion,' but no country or organization has specifically outlawed its use. No humans are known to have been parasitized by an Atoz, but it remains to be proven that this could not happen. The fact that an Atoz host cares for and protects the creature means that it is likely that a human host would take great lengths to conceal its existence. Some suspect that this may be a reason for their discovery only having been very recent. The WHO advises that Atoz tails should not be eaten.