So thanks to , I now know about Etsy seller section. In short: it is the best selection of terrifying textiles extant.
This is the one that got me:
Yep, that's "Squirrel Kicking Dog In Face Vintage Cotton Fabric". (It does what it says on the tin!)
I'm assuming this was originally intended for pediatric scrubs to be worn at the Our Lady of Inappropriate Cartoons Children's Hospital, but I'm open to other theories.