This is a great Shadow the Hedgehog shirt. Side-jumping shadow stars alone, without any other characters, which is a bit unusual. He doesn't look overly depressed, and the pose is nice and exciting. The background has a Japansese word (likely his name) scrawled in red shiny reflective paint.
In the detail shot, you can see the shine, and the fact that it's made of many small lines. Behind that is a splash of gray for texture.
The black version of this is in Kiddie-Size only, and appeared first. Several months later, the gray variant appeared in normal-sizes. So if you want this cool shirt, Winter of 2008 is your time to pick up one you can fit into at Sears! This shirt is in the personal collection of SonicGear.