Hei Yu was very much a Ninja Kitty -- she used to get great joy from chasing squirrels through the trees. Not up trees -- through them. From tree to tree to tree!
Both she and the squirrels obviously regarded this as a game -- the squirrels used to (for all the world!) sit on the back porch saying "Can Hei Yu come out and play?" (They also came around for their crackers and peanut butter, but the "Can Hei Yu come out" was a different pose altogether.)
We'd let her out (Hei Yu use the cat door when there was someone available to open a People Door?? Puh-leese --!!), and the Mad Tag Game would begin. Up the big oak, and all around the neighborhood without once touching the ground -- complete with sudden drops and huge flying leaps to bridge the gaps.
Scared us to death on occasion -- but she'd finally come prancing back home, just as happy and proud as could be. I swear she had invisible wings, and maybe a parachute, too... Never an injury of any kind, not even a scratch or a bruise.
She kept it up well into her teens -- until she moved down here, and we could no longer allow her outside. (We live on a very busy street now, a main drag to the beach, and she didn't know from Traffic.)
Buffy and Herkimer were Ninja Kitties, too -- of the Watch Cat variety, not the levitating kind. Buffy once trapped the gas man in our cellar for almost an hour, and the two of them put some very impressive gouges in a workman's boots when he delivered our new washing machine.
Buffy's idea was that people could come in, but they bloody(!!) well would not be permitted to leave until we okayed it -- especially not with our (old, but that was Beside The Point) washing machine!
She obviously trained Herkimer in this philosophy when he was just a kit -- one was wrapped around one of the poor man's ankles, the other took on the second ankle. Thank God the deliveryman was wearing those butternut-colored high-lace work boots, or he would've been very torn up! Half-inch-deep gouges in the heavy, cured leather...
As it was, he was well-scared -- they both sounded impressive, as well as being impressive! Such loud growls, yowls, and banshee wails --!! <shiver>
From that day on, we were very careful to be sure they were locked up when anyone delivered anything. Lawsuits we didn't need -- even though I rather suspect a big tough deliveryman might shy away from telling his drinking mates that he was suing because he'd been injured by a pair of kitty-cats... <giggle>
(Yes, you know and I know that cats can cause some pretty impressive wounds, but would his friends realize that? I think there just might have been some laughter around his regular watering hole...)