Hmm...maybe there is a catch. From what I watched, I believe the reason why the snake appeared was because of the magic practice ploy was doing and I'm kind of puzzled as to why yard got sick. From what? Being scared is what ploy said, but yard is mischevious and not to mention very brave after the way she attacked the snake from behind with the bow and arrow to help paul, so she would get sick over fear? Ploy said she sucked he snake poison out of paul's would but maybe Yard did and got sick because of that? That's my theory.