Quinlin has an indestructable hard plastic ball that she will do vertually anything for! I placed the ball on top of a ladder to see how much she really wanted the ball. Quinlin's first reaction was to bark at it to come down, but when she figured out that wouldn't work she began climbing. It only took about 10 minutes for Quinlin to figure out how to climb that ladder to get to her ball. The ball is as they claim "indestructable", but unfortunately it wears her teeth down so I only get it out if she has gotten out of the fenced in area. All I have to do is bounce it on the pavement and she comes running from one street over.