Sonic gets in on the "ugly Christmas sweater" trend?
It seems so, with this! Unlike the previous offerings which were tees designed to look like sweaters, this one is the real deal. It is woven out of sweater-strands, so the design you see here is woven directly as part of the fabric. It's all as bright a red as possible, with rows of white pointsettia flowers, pine trees, zig-zags & yellow rings. Classic Sonic in the winged-ring is right in the middle, but the bottom banner has been changed away from the logo & now spells "Merry Christmas".
This is an adult size only item, and is rather costly at at least 50 dollars because it's a real sweater. It appeared in late 2016, and should be in the Gear Store unless it sells out. It's up to anyone to judge if it is fun or tacky, though.
*This was first a UK only item, it is now a "2-places" SHARED item where it's available in both at the same time.

At the right is another one in time for the holiday season 2016/winter, Numskull produced this sweatshirt.
It's adult sizes only, and 'pixel styled'. It has Green Hill's ground, but the background has been changed to snowy pine trees & large with tiny snowflakes are dotted all around. In the distance, Eggman is flying in his Egg o Matic. The Sonic sprite is rather large, & he's sort of just...standing there. They didn't choose a pose or anything, he's just stopped. It's a little 'static', but it may have been meant to resemble one of those 'ugly xmas sweaters' that are trendy at the time.
This is fairly costly, since it's a thick sweatshirt for adults, it's likely to be around 40.00 or so. It appeared on Amazon for a while, but where else was it sold?