The Men in Black (MIB) are men dressed in black suits who claim to be government agents who harass or threaten UFO witnesses to keep them quiet about what they have seen. It is sometimes implied that they may be aliens themselves. They have been sighted worldwide including Britain. Whatever their purpose they are a threat.
They are described as always being clean and their appearence is said to be somewhat not human leading some people to belive they are aliens. They normally appear after UFO and other supernatural sightings, even people who claim to have seen monsters like El Chupacabra are sometimes paid a visit by the Men in Black.
Whatever the Men in Black are they appear threatning to anyone who has seen anything out of this world and no Government has admitted to know anything about the Men in Black.