This is called the "Warhol Fleece Sonic"
It's Just Funky, making more fleecy-fabric blankets in 2021. It is called "Warhol" because of the famous modern artist Andy Warhol. This artist was known for putting multiple rectangles/squares with objects (or the same object) in them, and then changing the background color, square by square to something different. This method of making paintings gained acclaim on canvas because nobody ever thought to do it before, and it was unique. (Ex. makes you look twice at a soup can or something common by messing with it as art)
So, here comes the blanket with 4 characters, each with a different (somewhat garish on purpose) background color. Sonic on too-bright yellow, Knuckles on ok blue, Shadow on slightly confusing red, and Tails on a green that's really not great. They chose lesser-used art like shrug/smug Sonic, faced-away Knuckles and hands out Tails.

This is large, at 45 x 60 inches, so there will be a lot of space with these very bright colors when you lay it out. It's about 35 dollars and may be at Target online, but should be elsewhere as well.