Getting hexed while trick or treating doesn't do anything
I'll second this.
I have seen one user who seemed to have been hexed, but I've been hexed 5-6 times so far with no apparent changes to my avatar.
I third this. I've been hexed twice now and haven't seen a change either time.

I'll fourth this. I have been hexed a lot of times and had nothing happen.
Same here :( I hope we aren't missing any new ones!