Our kelly LOVES our empty water bottles. It's the noise from squeezing the empty bottle. While we drink from one she waits patiently for us to drop it. And as soon as we tear the paper off, she's already dancing and jumping for the bottle.
*NOTE OF CAUTION*
Do not just leave the bottle with your pet. when Kelly has successfully crushed the bottle full of hole she starts to knaw on it. and she chews little hard peices of the plastic come out. And there is blood on the bottle as well. So please monitor your pet's activity with it.