There are no such things as aliens. The Creator of the didn't build an infinite playground just to stick mankind on one rock orbiting one star in one galaxy in an unfathomably immense and expanding universe. The Bible speaks of different kinds of angel and other creatures in heaven and of their appearances on Earth. It also would be naïve to think that everything there is to know about God’s creation is written in one book held by one creation on one planet.

Jesus would not be surprised at the appearance of others of God’s creation.