Andromeda Strain

The Andromeda Strain is an extraterrestrial microorganism from the Michael Crichton book of the same name. It is a deadly contagion that causes rapid blood clotting, which threatened to infect everyone on Earth.

Physical Appearance
The microorganism has a crystalline structure, heavily implying it was created by an intelligent race of some kind.

History
A military satellite crashes down to Earth somewhere in Arizona, but contact is lost abruptly. Aerial surveillance reveals that everyone in Piedmont, Arizona, the town closest to where the satellite landed, is apparently dead. The duty officer of the base tasked with retrieving the satellite suspects it returned with an extraterrestrial contaminant and recommends activating "Wildfire", a protocol for a government-sponsored team of scientists intended to contain threats of this nature.

The Wildfire team, led by Dr. Jeremy Stone, believes that the satellite—intentionally designed to capture upper-atmosphere microorganisms for bio-weapon exploitation—returned with a deadly microorganism that kills through nearly instantaneous blood clotting. Upon investigating Piedmont, the team discovers the townspeople either died in mid-stride or went "quietly nuts" and committed bizarre suicides. Two survivors—the sick, Sterno-addicted, geriatric Peter Jackson and the constantly bawling infant Jamie Ritter—are biological opposites who somehow survived the organism.

Jackson, Ritter, and the satellite are taken to the secret underground Wildfire laboratory, a secure facility equipped with every known capacity for protection against microorganisms escaping into the environment. Wildfire is hidden in a remote area near Flatrock, Nevada, sixty miles from Las Vegas, concealed in the sub-basements of a legitimate Department of Agriculture research station. Dr. Hall is the only scientist authorized to disarm the automatic self-destruct mechanism; he is an unmarried male and thus presumed to make the most dispassionate decisions during crisis.

Further investigation determines that the deaths were caused by an extraterrestrial microbe transported by a meteor that crashed into the satellite, knocking it from orbit. The microbe contains chemical elements required for terrestrial life (hydrogen and carbon) and appears to have a crystalline structure, but lacks the DNA, RNA, proteins, and amino acids present in all forms of terrestrial life, and directly transforms energy to matter with no discernible byproducts. The microbe, code-named "Andromeda", mutates with each growth cycle, changing its biological properties.

The scientists learn that the current form of Andromeda grows only in a narrow pH range; in a too acidic or too alkaline growth medium, it will not multiply. Andromeda's ideal pH range is 7.39–7.43, within the range found in normal human blood. Jackson and Ritter survived because both had abnormal blood pH (Jackson acidotic from consumption of Sterno and aspirin, Ritter alkalotic from hyperventilation). However, by the time the scientists realize this, Andromeda has mutated into a form that degrades the lab's plastic seals and escapes containment. Trapped in a contaminated lab, Dr. Charles Burton demands that Stone inject him with a "universal antibiotic"; Stone refuses, arguing that it would render Burton too vulnerable to infection by other harmful bacteria. Burton survives because the mutated Andromeda is no longer pathogenic.

The mutated Andromeda attacks the synthetic rubber door and hatch seals within the Wildfire facility, rapidly migrating toward the upper levels and the surface. The self-destruct nuclear weapon is automatically armed when it detects the containment breach, triggering its detonation countdown to prevent the spread of the infection. As the bomb arms, the scientists realize that given Andromeda's ability to generate matter directly from energy, the organism would be able to consume the released energy and ultimately benefit from a nuclear explosion, forming a large indestructible biofilm within a day.

To halt the detonation, Hall must insert a special key he carries into an emergency substation, one of which should be accessible from any location in Wildfire. Unfortunately, he is trapped in a section that, due to an oversight, has no substation. He must navigate Wildfire's obstacle course of automatic defenses to reach a working substation on an upper level. He barely disarms the bomb before all the air is evacuated from the deepest level of the Wildfire complex, which contains the remainder of the team and their assistants. Andromeda is suspected to have eventually mutated into a benign form and migrated to the upper atmosphere, where the oxygen content is lower, better suiting its growth.