A doe, a fawn, a very foolish cat, and an unfortunate dog. This video has become a classic. Note how the graceful mother deer can suddenly lunge, batter, and spring through the air with tremendous speed.
I've watched this several times, and I notice a few things: the cat must have the scent of the fawn all over its fur, so I wonder that the mother deer tolerated it for as long as she did. Maybe the cat was too small and clueless to worry about. When the fawn suddenly lay down, I wonder if it was instinctively responding to the scent of the large dog, a serious threat. It may also have triggered the shockingly unexpected response from the doe.
She exploded into action in a frightening way and quickly dispatched the dog. I wonder if it survived. This is pretty intense and illustrates the protective maternal instinct. We tend to think of a doe as a gentle creature, i. e. Bambi's mother, but they can be as fierce as elk in the mating season. Don't mess with them!