There's a lot we don't know about the universe around us, which has given us quite a bit of room for speculation. The field of extraterrestrial theory is a pretty big one, but what follows are three of the more bizarre theories relating to alien origin/identity.
The Aliens are Demons Theory
“As we enter the 21st century and a new millenium, Satan has devised the delusion that mankind is entering into an important evolutionary phase - a New Age. The push for "global enlightenment" has now extended to the vast reaches of the universe, into what could be deemed as a "space" religion. However, once this nebulous veil is lifted, a definite correlation emerges between the UFO/Alien phenomenon and occultic/satanic activity.”
No, those aren't the Ziggy Stardust linear notes, that's the opening paragraph to “Demon's in Aliens Clothing,” an essay by Ron Patton that argues that the extraterritorial we've all come to know and love are actually agents of Satan in the modern age. We're working on a bit of a word count here, but we'll try to condense it the best we can.
Ron starts by tying together Egyptians, Babylonians, Aztecs, Incas and Mayans on the basis of human sacrifice and the “abrupt” end of their civilizations. Then he connects the gods these societies worshiped to creatures in the Bible. The Phoenix, for example, is likened to a cockatrice. Continuing to ride this Bible train, he brings up Nephilim (giants in Genesis, the results of angels crossbreeding with humans) bear a striking resemblance to aliens in Nordic culture.
To tie all of this what the hell together, Ron brings up the alien abduction of Sky Ambrose. Ambrose told her story on a 1994 radio program. She insisted that aliens had abducted her and her friend, informed them that they (the aliens) we're the caretakers of humankind, the universe was rhythmically balanced, the the Earth was God's soul (this is likened to paganism), and the next race would be crossbreeds of humans and aliens – boom, Nephilims. Mind blown.
Ron ends his piece by stating clearly his belief that aliens are literally demons, and that the concept of universal enlightenment will only leads us back to the ways of the ancient civilizations: human sacrifice and Devil worship.
If that was a bit too much for you, now would be a great time to grab a drink, because we're just scratching the surface here.
The Aliens are Angels or God Theory
Coincidentally, there's another side to the “aliens are evil demons” coin that cites some of the same evidence. For those wanting to look into the Nephilim/giants thing, the apocryphal Book of Enoch expands on the story with greater detail: two-hundred angels called Watchers defied God to breed with human women. But because they hadn't done enough to piss off the Almighty, they also shared “forbidden wisdom” with humans, which included metalworking, meteorology, sorcery and astrology. These watchers became fallen angels when God ordered them to be locked in the ground. He then sent the Great Flood to wipe out the Nephilim and humanity, because seriously, no means no.
Chuck Missler and Mark Eastman, proponents of the ancient astronaut theory, have floated the idea that the Watchers were actually extraterrestrials looking to give mankind a helping hand (and apparently to get a little somethin' somethin' on the side). Erich von Daniken, author Chariots of the Gods, takes this a creepy step further, suggesting that the angels that visited Lots family were a pair of aliens that destroyed Sodom and Gomorrah with atomic weapons.
In 1956 Morris Jessup suggested that there are Biblical accounts of UFOs in the Book of Ezekiel. In the first chapter, Ezekiel encounters a cloud that emits fire and lightning. The center of the fire appeared to be metal and housed four winged creatures. Each was accompanied by four metalic objects described as a wheel within a wheel that followed each creature's movement.
Finally, another widespread theory says that Mary was artificially inseminated by aliens and that Christ himself was an extraterrestrial.
These theories are most often associated with Erich von Daniken's book Chariots of the Gods. However, Jessup had made his claims years earlier and published several books on the subject. Despite being considered the grandfather of the ufologist movement by many, Jessup's work has largely been passed over.
Aliens are Lizardmen
Reptilians. Reptilians everywhere.
A theory famously championed by writer and not at all crazy person David Icke states that Reptilians, humanoid reptile aliens, live among us in secret underground bases and have infiltrated every form of government, controlling the fate of the mankind and the planet itself. They also drink blood. Spooky!
Surprisingly, or perhaps not surprisingly depending on how much faith you still have in humanity, Icke's theory has followers in over forty countries. Because of this prevalence other folks have taken the ball and ran with it, creating some very interesting (if not insane) theories about Reptilians. We're going to narrow our scope a bit for the purpose of this piece, but feel free to Google 'reptilians' later and make a go of it yourself.
Anyway, this website explains that Reptilians are proportional to humans. The giveaway is the scale-like skin and the face's apparent dragon-like features. You're probably wondering “when did these people last see a dragon?” Unfortunately, we don't have that answer off hand, but we're pretty sure there's another web page for that somewhere on their servers.
Along with the physical description we're also told that Reptilians have an interest in Earth because it was once one of their ancient outposts, and they seek to take it back because their own planet is no longer capable of sustaining life. They've infiltrated the planet with the purpose of enslaving us or killing us, apparently depending on the mood of the writer.
Proponents claim that there are nearly two-thousand Reptilians walking among us, which includes (but is certainly not limited too) George W. Bush, Barack Obama, British royalty and even Boxcar Willie. That's right, people: they've come for our country music hobos. Literally anyone in a position of power (or with a recording contract, we guess) is a lizardman. One list can be found here.
If this sounds slightly familiar to you then you've probably seen the television series V, which sees disguised lizardmen take over the planet. However, the origins of that idea being a reality are much older, dating back to a 1935 article from the Los Angeles Times describing the discovery of underground cities belonging to subterranean lizard people.