The "Final girl" is the girl or woman in horror films who is the only survivor, who either ends the evil or escapes. Carol J. Clover popularized the name. Wikipedia notes, "During the final girl’s confrontation with the killer, Clover argues, she becomes masculinized through "phallic appropriation" by taking up a weapon, such as a knife or chainsaw, against the killer."
I do wonder about people who see phalluses everywhere. As Freud noted, sometimes a pipe is just a pipe. The final girl does not become masculinized—she takes charge of her life by using what's available to save herself. Symbolically, she comes of age. The change has nothing to do with masculinity and everything to do with adulthood, where we must kill monsters and then live with our wounds.