Here is a special Sonic Generations items. The first is a fun Sonic shoe keychain which was an exclusive pre-order bonus from the store "Big W" which seems to only exist in Australia. The shoe seems quality/ a reasonable size, plus it becomes a fun 'in-reference' since Sonic himself isn't anywhere around.
Here's a better look at the "Sonic Generations Shoe Keychain". It appears MIB on an earlier page, but that photo doesn't reveal the special logo on the shoe sole. This also shows what type of key clip it has, and the little chain. It's quite a nice sculpt for the shoe & a fun idea for a bonus. It came with the Generations issue of Nintendo Magazine.