The concepts of alien life and alien
visitation of Earth are fundamental aspects of Intervention Theory.
Several races of these beings are consistently described by
credible abductees, depicted below by artist David Chace. Perhaps the
best known are the iconic
gray-skinned, black-eyed "grey" aliens, but also known are
(from top left) Reptilians, Pleadians (or Lyrans), Anunnaki, (and from
bottom left) Blue Men, Small Greys, Tall Greys, Grey-Human Hybrids,
and Grey-Reptilian Hybrids. Not shown, but also well known, are
a type that resembles bipedal praying mantises, and are appropriately enough
known as "Insectoids."
Theory posits that humans are a product of genetic engineering,
combined with hybridization of the native primates of
Earth with the Anunnaki, which strongly resemble humans in many
ways. After all, the
historical texts do say that the "gods" (aliens) made us "in
their image, after their likeness."