The phrase "alien threat" is correct and usable in written English.
It can be used in contexts discussing potential dangers or risks posed by extraterrestrial beings or forces, often in science fiction or conspiracy theories.
Example: "The government has been preparing for the possibility of an alien threat, conducting research and simulations to understand how to respond."
Alternatives: "extraterrestrial danger" or "foreign menace".
It was the Minuteman worldview wrapped up in one sad little psychodrama: The alien threat, so scary, yet so imaginary.
Look at any press shot of electronic it-girl Grimes and she radiates a kind of fashion-forward alien threat.
In the third act of this grand space opera, your character, Commander Shepard, must accomplish nothing less than saving all life in the galaxy from an alien threat.
The conflict between Seaton and DuQuesne continued in Skylark of Valeron (1934 35), but they united to fight an alien threat in Skylark DuQuesne (1965).
Early games kept the stories simple, but it wasn't long before these representations of space offered more than merely a place to defend humanity from an alien threat.
Reagan revisited the idea two years later in a speech at the United Nations: "I occasionally think how quickly our differences worldwide would vanish if we were facing an alien threat from outside this world".
In "2001", the monoliths were doors of transcendent perception; in "3001" they become banal and easily dealt-with alien threats.
Doctor' companions Ian Chesterton, Barbara Wright and Clara Oswald have all worked at the fictional school, where students will be seen fighting off alien threats to London.
Here, he becomes a member of Torchwood, a British organization dedicated to combating alien threats.
She and the Doctor subsequently leave Jack behind on Satellite 5. Harkness returned in 2006 as a character of the spin-off series Torchwood, in which he is a member of the Cardiff-based Torchwood Three in combating alien threats and monitoring a spacetime rift which runs through Cardiff.
Or will it turn out that our paeans to non-violence were just cynical tactics in an amoral international power contest staged by militaristic Israeli and American right-wing groups whose elective affinities lead them to shape a common narrative of the alien Arab/Muslim threat?
