This basic horror plot structure offers a number of typical variants : the protagonist may actually be directly or indirectly responsible for summoning the other a violation that places even greater responsibility on her to restore the normal world. The protagonist may also have to enlist the help of a mentor or apprentice, or even sacrifice herself, in order to defeat the antagonistic other Sometimes the protagonist actually becomes the other. She becomes infected and attempts to deny, and then hide, her encroaching transformation. The may pursue a solution but ultimately faces the decision to either destroy herself or face a complete metamorphosis. Oftentimes, as in similar science-fiction stories, she is somehow saved by the power of her own humanity.