I think my 9 mo old used to work at the airport. ANY (and I mean any) unattended bag he finds, he must first attack from the outside, attack from the inside, sit in it for a while, and then go on his merry way. It doesnt matter what type of bag it is - plastic bags, paper bags, canvas bags, duffle bags, pillowcases (pillow bags), computer bags, book bags, even my tool box, which is really a duffle bag of sorts.
It always happens...
A: That's a cat for you. Every box that comes in the house sticks around for a few weeks before being recycled as my cats amuse the hell out of themselves with it.
They like hiding that's what they would be doing in nature to catch prey. Hide and then pop out and mess the critter up. Just a cat and quite a normal one. Maybe he is bored and needs some more play time and toys.
