Okay, so I know I'm super late, but my interpretation is that something got in through the window (I know the crack is super small, so it's possible it got in through somewhere else and broke the window along the way) and fought with the dude - I think he might be a modern-ish caveman because of his scraggly hair and square head - and was killed and chopped up into meat. Morbid, yes. Nonsensical, yes. The only thing I could come up with? Yes.