Whoa.
https://www.footballoutsiders.com/dvoa-ratings/2021/dvoa-week-4-bills-move-no-1-dominating-defense
“But the Bills are the big story, and we've got a lot of fun data to share about the incredible defensive performance they put together on Sunday. Right now, with the current opponent adjustments, the Bills come out with -134.4% defensive DVOA for Sunday's win. That would be the best defensive performance in a single game ever measured by DVOA, going all the way back to 1983.”