I've just come to this thread. I hadn't heard of the XL Bully. A week ago I set off to the Co-op for milk. After about a hundred metres or so I was attacked by a dog from behind. It ran at me and sank its teeth into my upper leg. The force of it hitting me there took me down. My right temple hit a parked van, and face hit the kerb cutting me at the eye brow. This injury bled - a lot. The dog moved its bite to another part of my leg and was hanging on still from behind making it difficult to tackle. It wasn't wearing a collar so I couldn't easily get hold of it.
Eventually I managed to get a few punches into the side of its face after I managed to roll on top of it. It took me a couple of minutes of punching to get it to release. Both of my hands were bleeding quite badly from attempting to release the dog.
It then just ran off. No sign of the owner. I say 'owner' but I don't think we humans are entitled to say we 'own' animals.
A friend later told me about the XL bully. So I googled it and sure enough, that looked very much like the dog that attacked me.
One of the bite marks on my leg after a week of healing ...