It was play time and I had some clean toilet paper in my hand ( use it for nesting ). I was crumpling it and moving it around in my hand. Mark came up to me trying to grab it from me. He then started nipping a bit, and then each bite got harder and harder. He even got puffy and I had to pry him off me a bit and put him back in his cage to calm down. This all happened in about 25 seconds and I was bleeding a little because of it. He is so sweet and I have never been hurt by him before why would toilet paper in my hand anger him so much? The sound?