Because Guardians of the Galaxy is the hot shit right now (I've seen it 14 times already because I live in the sewers below a movie theater like a cross between a ninja turtle and the Phantom of the Opera), this is the Groot costume made by Calen Hoffman of Propcustomz. Clearly, Calen will be winning any costume contests he enters this Halloween. Except mine. I judge based solely on bribes. "That's unethical." No, that's life. "Who won last year?" Some rich guy. "But what was costume?" No costume, just rich.
Keep going for a couple mores shots, but check out this link for an Imgur gallery of the build process.
Thanks to E V I L A R E S and bill, who are already hard at work training racoons to act like Rocket Raccoon for their Guardians of the Galaxy group costumes.