The Grays are part of Earth's history - date and place of origin unknown though sometimes associated with Zeta Reticuli.
They are artificial intelligence, lack emotions, and have their own agendas.
They have taken on various forms since the beginning. Today we call them the Grays.
Their eyes are light, usually blue, protected by black oval computer lenses. Elongated heads. No hair. Spindly bodies. Short in stature. Four webbed fingers. No visible genitalia or reproductive organs. Telepathic communication or sounds beyond human range.
They can shape shift or create screened images in the minds of sentient life forms.
They travel through space and time in ships, wormholes, portals, other.
They allegedly had bases below the surface of the planet, on the moon, Mars, other planets, now all vacated.
If you understand Simulation Theory - the Grays were another insert (race) of beings linked to the journey of humanity.
Biogenetic experiments on humans created alien-human hybrids. The experiments ended in 2008 by design.
Their crashed ships helped humans reverse engineer much of current technology. What remains today are alien drones that monitor the planet until the simulation ends. It is all by design.
The most famous UFO crash was the July 1947 Roswell, New Mexico Incident that opened the door to modern Ufology - also by design.
Solux - Ellie's Gray Alien in a Crystal