Which phrase from the passage best supports the theme that humans possess the ability to be monsters

The reason we use monsters in literature then? The role they play? There is no singular one. But I personally believe that we use monsters to take everything we dislike about ourselves as humans, and also all of those animalistic instincts we suppress, and put them into one form. We lock those beings in a cupboard or shove them under our beds so that we never have to look at them. And we take them out when we want to create a story - when we want to speculate from far away and see what happens. In that regard, every piece of artwork ever developed starring a monster and a hero is a constructed, thoroughly planned social experiment.

Answer:[the warrior's] mouth, which moved - or so it seemed to me - independent of the words, as if the body of the stranger were a ruse, a disguise for something infinitely more terrible. (155)