I have a member on my team who acts like a boorish pig. He "borrows" my belongings without asking, almost as if he's entitled to it. Last time, I had some snack on my desk and he just took it to his desk and started eating it. People around me were in such a shock and I didn't want to start an argument so I jokingly said, "Oh yes, I saved it just for you. Please enjoy it and you are welcome." He simply says "Thanks" and finished eating it and left the garbage on my desk.
This guy is our office's "all star", very popular, loves attention, and frequently likes to boss people around even when he's only a developer. Today, a project manager got very angry with him for shifting his resources around without asking.
What can I do? It's hard to deal with him since he's so friendly and likes to laugh things off.