Here's a shirt confirmed in 2 places...
This is an Old Navy item, but what's unusual about it, is that it can also be found on Amazon. Generally, with Old Navy their stuff, if it is in their physical store is always an exclusive for them. You can't buy it elsewhere. But, this is confirmed in both places. It is an all blue kids/teens shirt (but the XL/L should fit most) that appears in fall 2020/winter 2021. Through positioning of modern stock art for odd pose Sonic, fists up Knuckles and leaning Tails, they're arranged to be interacting with the shirt's slogan. A sticker-look red/white rectangle "Speed Zone" is being 'peeled' by Sonic to reveal a black 'space area' out of which the Tails & Knuckles art are set to look like they are climbing/flying. It's a creative use for the design, which results in a fun scene that's not like other tees. This should be about 14.99 at Old Navy but they often have sales. This is in the SonicGear collection.

In the gallary is a similar colored shirt from Bio World. Bio World keeps active in 2021/winter season with this tee for kids.
It's all blue with the slogan "Can't Stop This!" in curved white lettering at the top. It has modern jumping-twist Sonic in a red circle. This design uses the weathering or faux-wear to create a worn, crackled look on the paint of the art. This is a bit unfortunate because modern Sonic doesn't need a 'vintage' look (Faux or not), and it helps the shirt look even more worn out, even faster. (Little kids often wear out their things)
This is unknown whether it's little kids only (as per model you see here) or if it's one of those where it's sized up through teens so more people can get it. Where is this sold? How much is it?