I my English class, we just finished writing an essay about why we create monsters. Some people say it is because monster movies draws to a lot of audiences. Some people say it is because monsters represent the evilness of humanity, and by watching monsters, we can establish a sense of normality (since monsters are “abnormal”).
That could be one option. Another question would be, “why do we go to the movie theatre to watch horror movies?” Aren’t we scared of monsters and ghosts?