Here's an uncommon 2-pack.
This NKOK 2 pak is seldom-seen, and contains both Shadow & Sonic in the All Stars Racing Transformed vehicles. Shadow's seems to be the 'hover mode' one while Sonic's Speed Star is in it's normal car mode. These also should have been available individually packaged as well...and likely around the same time, so exactly why a 2 pack was created is unknown.