They're bringing back Sonic Adventure 1 style with this shirt.
This oddly tangled pose Sonic art was big around the time of Sonic Adventure 1. They've surrounded it with blue flames, the outsides of which have shimmer blue paint used. The Adventure logo appears at the bottom, which is only mildly curious due to their logo-mixing from earlier shirts. This is another Top Heavy offering, a black Tee in teen/adult sizes available at Sears in winter 2008/early 2009.

This variant has the same design, but with charcoal outer black/long.