I looked up the meaning of the phrase "cat's out of the bag", and was a little surprised to find out that it (maybe) originally referred to the practice of substituting a cat for a pig in a bag. I guess they used to sell pigs in bags? If the bag was opened, and the cat came out the jig was up, and you knew you were getting false goods.
However, for anyone who has tried to put a cat in a bag knows, it's almost impossible to get them in back in there, in a more literal sense.
Big thanks to my friends Nathan and Patrick for picture taking and bag holding!