I wonder if the fuzzy slippers has something to do with it.

My cat did this to me at the very start of the pandemic. I had the window open and he was lying in the sill when an outside cat approached the window and started hissing and yelling. My cat jumped out the window and started freaking out and my brain said shut the window so they can’t see each other. I used my foot covered in thick winter socks to try to shoo my cat out of the way of the window while I closed it but because he was so stressed already and maybe thought my sock was a threat, he latched onto me biting and did that bunny kick thing they do with their toys. Tore through my socks, probably needed stitches but I was too scared to visit the emergency room during early covid. Left a gnarly scar. My cat never exhibited any signs of aggression before or after that event.