What to wear: Unless the person reading this is Shaq, we're going to go ahead and assume you're not 9 feet tall, so don't worry about your size. This costume is a little tough, though, considering the undead Gregor Clegane rocks a full suit of golden armor. You can always wear a gold, long-sleeved shirt and pants and then just buy a helmet if you want to keep things simple. Just make sure you make any visible skin look like the gray, rotting flesh of a corpse.
How to act: Totally silent and totally terrifying.