Bag + Cat + Gravity = Ouch
Cats love bags and boxes. They are, in fact, infamous for cramming themselves into tiny spaces. Unfortunately, sometimes these spaces aren't as stable as they think.
Ouch. That's a cat who really wishes he was let out of the bag.
Fortunately, the cat was fine; it was a much shorter fall than it looks. The only thing injured was the cat's pride. Don't worry, kitty. We've all had our fail moments. Just maybe stay away from skateboards.