cats and plastic bags
they all love it.
my cats love all bags actually, my GF quickly learned to close her bags as they will climb inside and search it for toys.
they also quickly learn the usage of them, once i come home with a bag, they wait by the fridge as they know i will open it to put the things inside, just as they will run to the front door when i fetch my keys from the desk.
i usually do not let them play with the bags as most plastic bags have color prints on them, i don't think they are healthy and the sound annoys me after a while. instead i give them a fresh paper ball.