It's a Plaid Poncho, I think
Is it a shawl? Is it a ginormous scarf? Is it a blanket? Or... as one MIGHT suspect... is it the latest rendition of your traditional plaid poncho? Sans head hole and a whole lot more versatile, I'm way beyond caring about terminology at this point. I can wrap a belt around this thing, cozy up with it in front of a movie, or wear it as an oversized, ultra-trendy scarf. Who knows, I could probably even lay it down on the grass and arrange a picnic on it. But I'll wait for the warmer months to roll around, and in the meantime, it will be my cozy, undefinable pal.