I believe that the strong delusion that the Bible talks about will be a deception involving demons that pose as extra-terrestrials. I believe there will come a time, perhaps during the Great Tribulation, when demons are allowed to appear publicly as extra-terrestrials. Something right out of the movie, "The Day The Earth Stood Still."

They might say something like this:

We are here because mankind is about to make an evolutionary leap forward. It will be a time of happiness, health, peace, and plenty. It will be heaven on earth. The only thing holding it back are the primitive monotheists. Those who believe in God. They must be eradicated like a disease for the good of mankind.