The term Greys denotes a style of alleged intelligent, humanoid, extraterrestrials appearing in folklore, popular culture, and the pseudoscience of ufology. In particular, they are a common motif in close encounter and alien abduction claims. In abduction claims and popular culture, several commonalities of appearance tend to typify "Greys."
They are typically depicted as gray-skinned diminutive humanoid beings that possess reduced forms of or outright lack human organs and anatomical components. Their bodies are usually depicted as elongated, small chested, and lacking in muscular definition and visible skeletal structure. Their legs are shorter and jointed differently than one would expect in a human. Their limbs are often depicted as proportionally different than a human's; their humerus and thighs are the same lengths as their fore-arms and shins, respectively. They may have 3-5 fingers and may be depicted as lacking opposable thumbs. [Wikipedia]