These are keychains & phone charms by Cospa.
They're cute on purpose! Adorable mini versions of Sonic, Tails & Amy are drawn/styled to look like they are being pulled or held up by the loop that attaches them to the chain or cord. Amy's dress-back is pulled up, Tails' tails are pulled together, & 1 of Sonic's spikes are pulled up. Look at their cute expressions. The top row is keychain type, the bottom row is phone charm type. These are being sold at TGS (Tokyo Game Show) in 2013. They are about 630 yen each, or probably around 6 dollars or so. You can also see the prototypes / art for these over on Prototypes X.

At the image gallary you can see a fan photo, so you can see the thickness of the plastic & what it looks like when you actually get it.