Here's a Harry Potter craft I thoroughly enjoy - a howler hand-puppet. A howler is an angry letter that yells at its recipient. We first meet the howler in Harry Potter and the Chamber of Secrets, after Ron crashes his dad's car into the Wamping Willow and Molly Weasly is very, very angry.
This one comes from deviantart user mizutamari. It is such an original idea and it looks great! I'm jealous I didn't think of this first ;)