This is called the "Recover Gray Sonic Sweatshirt".
Why it's called that...unknown. But, here it goes, and it looks like the fabric may be fuzzy, or have some kind of texture? It is a mottled long sleeve gray sweat shirt, in adults sizes. It has a white-ink only design for the front with jumping-twist modern Sonic over a background rectangle of thin, angled lines. It uses a 'pixel' type chunky font for English at the top, then arrowheads and his name spelled out in Japanese letters under him.
The dark areas of Sonic are indicated as gaps in the line background/so he is all gray & white. This simplicity plus the action filled pose actually makes for an interesting design for the shirt. This should be an Amazon item in 2020/summer, but is it elsewhere?