I've also seen two dogs getting into a fight and one of them had that collar with spikes turned outside. I cannot describe you the mess it made, it pierced one of those dogs muzzle through its mouth because they were probably grabbing one another allover the place. Then they couldn't separate and it caused even more aggression, fear... wah! I was 14 when i saw this and i thought I was gonna die because I felt so bloody helpless. It's originally designed for flock guarding dogs that often get into fights with wolves/bear which I sort of understand, but using this thing as a training method ... horror!