Caleb's Apple
I found it interesting that the sign of "possession" [or witchcraft or what have you] that the audience gets to see as to Caleb is him vomiting a whole apple. It seems to me quite in context with his own "sin".
Caleb is beginning to wonder about sexuality [he looks to his sisters breasts] and finds a "beautiful" [I leave that one up for you to decide] woman in the forest that seduces him.
So, in a sense, he is committing the First Biblical Sin [which also involves an Apple] and the apple represents both defiance and luxury.
Thoughts?
You're more advanced than a cockroach, ever tried explaining yourself to one of them?