in addition to imagining through readings of newly discovered planets...I like to read the conspiracy part as well
in this case I tried to realize this :
"The body of Greys is more or less considered a vessel for higher dimensional beings to act in a lower density environment like the earth. An Is-Be in a Grey body can leave or invade this vessel according to their will much like an avatar. It is mostly designed to be a tool for example to steer spaceships, like an interface between an Is-Be and a machine."
this description of gray aliens comes from random website by googling alien conspirancy