In fall/winter 2015, Kohls stores get this blue Boom tee. The shirt is all a royal blue with Sonic, Knuckles & Tails on it. They're all CG, with various textured backgrounds in fairly trapezoid shapes. Sonic's got his hand up, Knuckles raises a fist & Tails holds up a wrench. The logo is large at the bottom, covering the characters' feet.
This shirt should be in the boys/teens area, and appears despite the winter season of its release. Usually Kohl's items will be exclusive to that store, so if you want this particular design, you would need to shop only there to get it.