A Plush keychain of Sonic. It seems fairly well constructed for its small size, it's only about 4 inches, not including the plastic hanger top. The buckles are a bit mis-placed but the detail for his hands is pretty impressive on a plush of this size. This particular one was being sold by "Toys R Joy" over an Ebay Auction. They used to be fairly common, over ebay, after the time of SonicAdventure 1 had well passed, despite being from Japan.
With the right picture you can see his details are embroidered, and they did a pretty decent job with him proportions-wise. Over all, a good keychain to collect.