Having a DOG fetch a ball is so 20th century...

What you need is an eagle. It's interesting in the video above that the narrator comments that he isn't distressed by the eagle's bite, but fears (and is injured by) the talons. At the National Eagle Center I learned that the beak of an eagle is relatively weak because it is not designed to kill or rend flesh; rather, they kill and rip food apart with their talons. The naturalists there report that an eagle's bite is not painful, but in contrast the bite from a small seed-eater (cardinal, finch) will cut to the bone and cause the victim to collapse to the floor in pain.