I found a creepy glitch of my own. I was feeling retro and played some Hexen II. After killing a Medusa in the third level hub (which is Greco-Roman themed), her head ended up spinning around in the air. A few minutes later, it happened again, and more frantically. (Medusas in Hexen II also open and close their mouths repeatedly on death, so it would have been nice to catch a frenzied severed head repeatedly opening its mouth on video as well, but I’m too slow.)