My cat does the same thing...actually doing it now as I type. She loves to naw on the bag, lay on them like a blanket and play around with them. She likes to jump into the bags like a person jumps into a pile of leaves in the fall. I don't know what it is either about cats and plastic bags, but I'm sure to keep an eye on her so she doesn't injest any plastic. It'a ironic, you spend money on toys and they end up playing with your leftover grocery bags. Go figure!