That is the theory proposed by a certain faction of cryptozoologists who moonlight as UFO hunters. Several cryptozoologists have forwarded the notion that the Chupacabra is not like any animal known to man because it is not of this earth. Among the more hardcore of these true believers is that the Chupacabra was left behind by aliens to either conduct experiments or just to conduct a kind of havoc up we poor natives. (Or something far worse, which I’ll reveal later.) One element of this theory of the extra-terrestrial Chupacabra is that it is itself a hybrid creature created by native animal from the plant of our alien visitors and a four legged little earth dog. Or kangaroos. Or possum. Or armadillo. Or wild boar. The list goes on.
The alien Chupacabra, or so our cryptozoologists tell us (and exactly where does one get a degree in studying things like Bigfoot, the Loch Ness Monster, and El Chupacabra), is actually a rather sturdy and active creature by day and night. This otherworldly Chupacabra possesses something about it that sends other animals into a full scale panic at or even before the mere sight of his presence. The reason why nobody has yet managed to see a Chupacabra in action is because it has the ability to make itself invisible. There are animals that exists that can blend into the background so as to give the appearance of invisibility, but to the best our knowledge there is absolutely no animal whose ancestry can be traced back to the beginning of this planet that has the ability to actually become invisible. Those who have claimed to have come into contact with the Chupacabra almost always insist that the animal disappears from the scene so fast that it almost seems as if it actually did disappear. Into thin air.
Then there are those glowing eyes and the fact that a fair number of reports about the Chupacabra also mention incidence of UFO sightings. It should not be surprising in the least that when the writers of the X-Files decided to do a show about El Chupacabra that they introduced an aspect of alien visitation. As if a strange create that sucked the blood out of goats was not enough to keep us interested. The Monster Quest investigation, which as usual ended with nothing further to add to the story, went peculiarly lite beer on the issue of UFO sightings often being reported in conjunction with the sighting of a Chupacabra. But there it is. The mystery of the fact that none has never been captured, regardless of the weird dogs on Monster Quest, makes it quite possible that El Chupacabra is alien in nature. But would be the point of the aliens leaving behind such a small animal? Ah, here is where it gets interesting. There is another X-Files episode in which the Chupacabra is mentioned. It is the fan favorite titled Bad Blood in which Scully infamous asks of Mulder, “It’s not that Mexican goat-sucker” in reference to his excitement over traveling to Texas to check out exsanguinated cows. Turns out the Texas were vampires.
According to the alien story, that is exactly the purpose served by the Chupacabra. They have been left behind by the aliens to rid Earth of pesky humans through the means of a vampiric dog-like creature.