This adorable bit of costuming is the Big Bird Adult Accessory Kit, which can turn anything you decide to wear on Halloween (or whenever, really) into a cute, fun, and lively costume. Everybody loves Big Bird. He's a giant yellow bird whose best friend is a talking wooly mammoth. That's pretty cool. I wish we all had it so good.
With that in mind, it would behoove you to get a little bit of Big Bird's reflected glory by wearing the Big Bird Adult Accessory Kit, which comes with a plush shrug and a character headpiece.