Vashta Nerada


 * For the inhabitants of the Howling Halls, see Elemental Shades.

Vashta Nerada were swarming, carnivorous beings. The name meant "the Shadows that melt the flesh".

Biology
The Vashta Nerada are microscopic beings that live in swarms, thousands strong. On their own, Vashta Nerada are not a threat. They are very small; the Doctor claims that the dust specks visible in bright sunlight are single Vashta Nerada or a small swarm not yet large enough to be a threat to most life. Once they are in sufficient numbers, they are able to strip a creature to its bare bones in milliseconds and the Tenth Doctor once described them as "piranhas of the air". Vashta Nerada swarms are sentient and two spacesuit-inhabiting swarms developed the ability to communicate with the Doctor through the spacesuits' Data Chips. They were also able to coordinate their efforts and make the spacesuits walk, though only with some difficulty, and could walk slowly in a 'zombie-like' fashion. (DW: Silence in the Library / Forest of the Dead)

The Vashta Nerada live in the darkness and cast shadows when they enter the light - even to the extent of stopping the reach of light from fission lamps. On its own, outside of the darkness, a Vashta Nerada swarm looks like a shadow cast by nothing. They mimic the shadows of their prey in order to get close, which means staying in the light is the only option in order to escape. If someone has an extra shadow, it is already too late for them. Sonic technology is able to detect the difference between a Vashta Nerada swarm and an ordinary shadow.(DW: Silence in the Library) The Doctor believes they have no weaknesses (other than the light) and that the best thing to do was to run. (DW: Silence in the Library, WEB: Captain Jack's Monster Files)

Life cycle
The Vashta Nerada live on almost every planet which has organisms with meat, including Earth. On Earth they are born as microscopic spores in trees and live their lives in forests. These spores are resilient enough to hatch even if the tree was processed, even if the wood was converted into paper and into books, which explains why so many were present on the planetary Library. It was said that they are able to hatch and form into a swarm in minutes. (DW: Forest of the Dead).

History
Vashta Nerada have existed since the early Universe, and spread to many planets across the Universe. While these swarms are not common, they inspire a fear of the dark in most species across the Universe, since any shadow could be made of Vashta Nerada. According to the Doctor, this explains why young children are afraid of the dark. They know, at the back of their minds, that the Vashta Nerada are there. On Earth, the Vashta Nerada survive by scavenging meat from road kill.
 * How the spores originally got to different planets is unknown.

In the 23rd century, a temporal rift resulted in a group of hostile Vashta Nerada being transplanted from their home to arrive in the underwater city Poseidon 8 on Earth, along with a giant shark-like being. Fortunately, the Eleventh Doctor and Amy were able to defeat some of the Vashta Nerada by luring the diving suits they were using into a brightly-illuminated area; the Doctor later closed the rift and returned the Vashta Nerada to their original planet. (VG: Shadows of the Vashta Nerada)

In the 50th century one planet suffered a large infestation. The Library was attacked by over a "million million" (1,000,000,000,000) Vashta Nerada, due to the spores inside the books' paper hatching as well as from the wood the library was largely made up of. The 4,022 people on the planet could not be evacuated by the Library's computer and were 'saved' in its harddrive. The computer created a virtual world for them to live in and the planet was empty for 100 years until an archaeological expedition and the Tenth Doctor with Donna Noble landed on the planet.

Though much of the archaeological team was consumed by the Vashta Nerada, the Doctor was able to convince them to stop and give him a chance to return the people stored in the Library's computer. They agreed to give him a day upon reading about him in the library, in which time the humans were rescued and left the planet to the Vashta Nerada. (DW: Silence in the Library/Forest of the Dead)