We have a big kitty. 25 lb Mainecoon, he only has to warn a dog once that it has over stepped its bounds. We were pet sitting a friends dog over X-mas. First day the dog comes in the house and see's big kitty and decides to chase him. Bad idea, rumble, rumble, bark, hiss, fitt-fitt, YIPE, YIPE. I go in the room grab the dog and remind him myself that we dont chase big kitty in the house. So a week goes by without any further confrontation and I'm petting the dog and I feel somthing in its scalp. I pulled out a discarded cat nail that hafd been stuck in his head for a week.