Opossums "play dead" when threatened, so I've heard. It's true all right, as I discovered when I encountered this little guy on the trail. He became as still as a statue when he saw me, not even blinking, then verrrry slowwwly lay down, closed his eyes, and bared his teeth. Maybe he wanted to look mean just in case someone didn't believe he was actually dead? He remained motionless and didn't move at all until I was quite a ways down the path and he was sure he was safe. Cute little critter...sorry I frightened him, but glad he was only pretending. :)