Men in Black
No discussion of aliens is truly complete without a discussion of the Men in Black aka M.I.B.s. Many people after witnessing a UFO or alien have been approached by these strange men in black suits. The MIBs often claim to be government agents and threaten the experiencer to not divulge what they have seen.
Many in the UFO community believe these men to be aliens pretending to be human or even robots! Sometimes they have pale or grey skin, and look emaciated, although some have olive complexions and Asian features. They speak somewhat in monotone or almost robotic voice and are reported as having robot or machine-like movements.
They wear black suits and ties made of rather shiny material. Their clothes look in impeccable condition including shiny new shoes not showing any signs of the weather even when appearing in the middle of a muddy field!
If they arrive in a car it is always big and black. Some people have tried to trace the license plate unsuccessfully. They also often appear near black military looking helicopters.