This term is used in this work to refer to beings existing at a level superior to the human level and manipulating humanity and other similar lifeforms for their own ends.
We are not talking about strictly ethereal entities. They can appear as solid physical bodies, as exemplified by many UFO reports. These are however not native to physicality as experienced by humans. They occupy a realm with variable physicality and can project themselves into physicality as experienced by humans through use of technology or psychic power.
The idea of these beings as a human-like lifeform from some other planet is misleading. The various strange anomalies such as variations in the rate of passage of time, spaces being larger on the inside than outside and such effects suggest that these beings experience different laws of physics from what we are used to. Accounts retrieved from people having interacted with such entities suggest that people can be transported into this different level of reality and temporarily exist there in physical form. Thus that level does not appear as a fluid idea world and has a certain solidity. Also based on these observations there are living entities as well as inanimate pieces of technology in evidence.
We cannot construct an exact representation of this level based on human sensory experience. Accounts of high strangeness in conjunction of the UFO phenomenon and psychic experiences of humans however suggest that such a mode of being and perceiving is real. Otherwise we are limited to descriptions contained in various channeled material.
Different biological types of beings have been reported in this context. Most reports concern the so-called Gray alien, a somewhat humanoid 4 foot tall creature with large black eyes and a bulb shaped head. Another form is an 8 foot tall upright alligator, sometimes called a lizzie. Yet another is a Nordic looking human form. Still other forms such as insects are sometimes reported. To what degree these are physical forms and to what degree these are interpretations of the observers from something else is unclear. There appears to be consistency between reports describing these as solid beings. On the other hand, similar beings are seen walking through walls and materializing from thin air also. This suggests an inherent mastery of physicality, whether through technology or as an intrinsic feature of these beings.