U.S. recovered non-human 'biologics' from UFO crash sites, former intel official says | NPR

I have found this on wiki page of history of nano-technology

The term "nanotechnology" (which paralleled Taniguchi's "nano-technology") was independently applied by Drexler in his 1986 book Engines of Creation: The Coming Era of Nanotechnology, which proposed the idea of a nanoscale "assembler" which would be able to build a copy of itself and of other items of arbitrary complexity. He also first published the term "grey goo" to describe what might happen if a hypothetical self-replicating machine, capable of independent operation, were constructed and released. Drexler's vision of nanotechnology is often called "Molecular Nanotechnology" (MNT) or "molecular manufacturing."

Could be the non human biologic recovered. I think the NHI is nano tech combined with AI. Edit: if this was true the grey alien could be some kind of "robots"(?)