Nearly all monster stories depend for their success on Jack killing the Giant, Beowulf or St. George slaying the Dragon, Harry Potter triumphing over the basilisk. That is their inner grammar, and the whole shape of the story leads towards it. ↗
Some men have a silly theory about beautiful women - that somewhere along the line they'll turn into a monster. That movie gave them a chance to watch it happen. ↗
Whoever fights monsters should see to it that in the process he does not become a monster. And if you gaze long enough into an abyss, the abyss will gaze back into you. ↗