I bought Waldo a beach ball at a garage sale and did he ever have fun with it. He soon learmed to get a grip on it by biting the plug, then shake the ball. Then he wondered why it didn't roll well any more. After a little time, there was more duct tape on the ball than blue space (it is a globe ball). But it was fun while it lasted. I'll have to find a light, big ball that is a little more durable for doggie teeth. It was worth the quarter!