"Hey, who turned out the lights?"
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BBC One - Doctor Who, Series 5 - Vashta Nerada
The Vashta Nerada are ravenous hunters able to strip the meat from a body with a frightening speed and efficiency. They tend to avoid light, often concealed in patches of dark that resemble shadows, hence the general warning to 'Stay out of the shadows' if you suspect these creatures are close.
Doctor Who - the top ten baddies
The Vashta Nerada - A quite chilling concept from Steven Moffat, these microscopic swarm creatures inhabit the dark. Once they have latched onto you as their pray, there is little hope of escape. First Appearance: Silence in the Library Last Appearance: Shadows of the Vashta Nerada - Series 5