Golden Retriever puppy goes crazy over door stop

Lily is a 3 month old golden retriever puppy who has two speeds: full tilt and sound asleep. She plays with her toys with great enthusiasm, until she discovers the door stop. Who hasn't been fascinated with them at one point in their life? Lily forgets all about her dog toy and chews and paws frantically at the door stop, seeming to thoroughly enjoy the noise it makes each time it springs back in place.