Cryptoterrestrial UFO Hypothesis.

[sahgwa]

This  'new fangled term' also ties into recent buzz renewed rehashed about alien bases off California and Asian coastlines underwater.  'They've always been here' the meme goes , but I mean perhaps they showed up 4 thousand years ago.  Point is, it relates very strongly to USO's. 
Unidentified Submerged Objects or is it
Unidentified Submersible Objects or is it
Unidentified Submarine Objects. . .
R'lyeh
Yhanth Lei

And ALSO to underground!
DUMBs
Caves
Underground cities. 
Kingdom of the Faery
N'Kai 

cthulhu ftaghn.