Tarchannen

Note: This is NOT a PC or NPC / NRC rated species.

SPECIES
Tarchannen
Homeworld:	Tarchannen III
Quadrant:	Delta
Affiliation:	Unknown
Biology
Average Male Height:	173 cm (5 ft. 8 in.) to 198 cm (6 ft. 6 in.)
Average Male Weight:	68 kg (150 lb.) to 113.4 kg (250 lb.)
Average Female Height:	165 cm (5 ft. 5 in.) to 188 cm (6 ft. 2 in.)
Average Female Weight:	54.4 kg (120 lb.) to 95.3 kg (210 lb.)
Minimum Academy Age:
Life Expectancy:	180
Distinctive Features:
Playability
PRC Rated:	No
NPC Rated:	No

A member of the species exposed by an ultraviolet light

The species footprints and cells, from the Enterprise-D computer

The Tarchannen are a non-sentient species native to Tarchannen III. They have a characteristic mimetic ability that made them nearly invisible. A radiant reaction in the skin simulates light and acts as a kind of biological cloaking device. This, coupled with their low body temperature, makes them nearly impossible to detect.

Reproduction in the species is accomplished by embedding a parasite into the thymus of a host humanoid. The parasite then uses the host's immune system to spread genetic instructions, transforming the DNA of the host to match its own. This virus produces cells with weak cell walls, and contact with the cells themselves is not contagious.

In 2362, the 49-member crew of the Star Fleet outpost on Tarchannen III disappeared. The USS Victory was dispatched to investigate, but found no trace of the missing personnel. In 2367, the members of the Victory away team that had investigated the disappearance began to desert their post and return to Tarchannen. It was discovered that these crewmen, including Geordi La Forge, were infected by the parasite and transforming into the Tarchannen III species.

Lieutenant Leijten

In the case of Lieutenant Susanna Leijten, as observed by Doctor Beverly Crusher, the parasite had remained dormant for five years before beginning to transform Leijten's DNA. The patient first began to exhibit symptoms of anxiety. Tests showed that her blood chemistry was abnormal and that she had a histamine response (allergic reaction) to something unknown.

Dr. Crusher then performed a complete blood and tissue analysis, but the tests were inconclusive. Leijten began to suffer tremors in her hands, and increased visual sensitivity. Shortly after this she collapsed and it was discovered that she had blue vein-like growths on her neck and that two of the digits of her right hand had grown into one.

The patient's physical form continued to rapidly change. The growths soon covered her entire body and her eyes changed color. She developed a strong sensitivity to light and her blood pressure dropped. Dr. Crusher administered a T-cell booster to attempt to stabilize her immune system. An examination of a cell taken from her skin showed it to be identical to alien cells found during an earlier the investigation of the missing crewmen. As Susana was not herself contagious, Dr. Crusher was able to continue further study. She discovered the location of the parasite in Leijten's thymus, as well as the nature of its operation.
She was able to remove the parasite and regenerate the DNA of the patient.