I fed the story into Gemini and asked if it was written by AI. It said no way and for a variety of reasons. If this WAS written by an AI then they are certainly getting better at story telling.
Definitely an alien. I saw a movie that had this creature in it and it ended up spreading all over the city 20 metres high. Everyone died, except the pretty blonde woman and her hero.
Not quite sure how you distinguish an em-dash from a normal dash in this forum, however, if there is an em-dash in text then that can be a clue that it was AI generated. Not always, but often.