Back in Alpha 18, I was having a good ol time riding around a motorcycle when I spotted a large cluster of zeds. I decided I would ram one with my motorcycle, and jump off shoot one in the head, and then smash in the last one.... Unfortunately, I'm not sure it was a bug or not, but when I got off my motocycle at full speed, it clipped my character, and sent me into some kind of dazed animation with my character lying on the floor for about 5 seconds. I barely got out of that without being fully eaten... Since alpha 19, I've never seen this animation occur again, I don't think players can get stunned anymore, but not sure.