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. ↗
Most of the monsters... are based on some sort of mythology. Every culture and even some geographical areas have monsters and mythology that is their own. ↗
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. ↗