Halloween is over, which means some of you may have already jumped right into Christmas season. But before you go, do enjoy a roundup of the very best celebrity Halloween costumes of the year. Indeed, last night on social media, plenty of celebs showed off their Halloween digs, many of which are mighty impressive. There’s Oscar-winning director Alfonso Cuarón going full Shaun of the Dead right next to Shaun of the Dead star Simon Pegg dressed as The Shining’s Jack Torrance. And how about Martin Freeman as a Ghostbuster, or Brie Larson as Britney Spears, or …