Greys are a species of extraterrestrial that exists in many different universes. They're roughly Humanoid, but with pale, smooth grey or white skin and huge eyes that appear entirely black. In most depictions, they travel through space in starships that tend to resemble Flying Saucers, though they've also been known to use other types of craft. In most universes, they've been visiting Earth secretly for various reasons. Their actual name and intention differs from universe to universe.
- Greys are the common notion of what Aliens would look like from folklore. Many people believe they've seen aliens that match this description. As such, Greys have been worked into the mythologies of many different science fiction franchises.
In this universe, they control massive flying saucers that communicate through patterns of light and sound. While they sometimes frighten and abduct Humans, they seem to be generally peaceful and friendly. They made official first contact with Humans after giving certain humans recurring dreams about the place of meeting. ("Close Encounters of the Third Kind")
The Fourth KindEdit
While the aliens in this universe were never shown, thus making it unclear whether they are, in fact, Greys, it's heavily implied. Witnesses interviewed by Dr. Abigail Tyler in Nome, Alaska reported seeing a grey or white owl outside their window which, they later realized under hypnosis, wasn't an owl at all. These aliens seem to be hostile; to end Dr. Tyler's study of them, they abducted her daughter and refused to return her, proclaiming themselves to be God. They also speak in ancient Sumerian, implying a connection to ancient cultures on Earth. ("The Fourth Kind")
The Greys in this universe are known as the Skrit Na, and are one stage of a multi-staged life-form. That is, as their life progresses, they physically metamorphose, like a butterfly. They generally cause mischief by abducting members of various alien races. The Andalites tend to put a stop to their activities whenever the two races encounter one another. (Animorphs franchise: "The Andalite Chronicles")
They're called the Asgard, and, as their name suggests, they were the basis for Norse mythology after visiting the planet many times over the centuries. They're a benevolent race, and an ally in the fight against the Goa'uld and later against the Replicators. (Stargate franchise: "Stargate SG-1")
In this universe, a race of Greys have been living in tunnels under the Earth for centuries. They're part of an order known as The Silence. They're somehow able to prevent humans and even Time Lords who've seen them from remembering the encounter. In this manner, they've been manipulating Human culture for centuries. They're a malevolent race. (Doctor Who franchise: "Doctor Who")