The Monster, also known as the Smoke Monster by some of the characters, Cerberus by the DHARMA Initiative, or the nickname Smokey by fans, is one of the central mysteries on Lost. It was introduced as an unseen threat that dwelled on the Island in "Pilot, Part 1", and it has been encountered by the survivors many times since, sometimes attacking people and at other times sparing them. Its appearance is that of a freely-moving cloud of black smoke that can split into several smaller clouds. It produces a variety of loud noises, is capable of uprooting trees and foliage, and occasionally produces brief flashes of bright light which project images from a person's past. It can seemingly take alternative forms (including human), through which it appears to "judge" the people it encounters. Its origin and true nature are still unknown, but it is presumed to be a guardian of sorts, as Danielle and Robert have referred to it as the Island's "security system," and Ben has demonstrated the ability to summon it in order to protect against threats to the Island. Its apparent connection to both the Temple and an ancient stone doorway furthers adds to what the producers said that the Monster has existed since the time of the Island's earliest inhabitants, if not longer .
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