I've never witnessed a bullet "bounce" off an animal, but I have read about it a lot on the internet.
Perhaps when you grow up you'll come to understand that bullets and balls don't always bounce back the same way the came. Mostly, it looks more like an incidence and reflection being more equal.
That's pretty much what happened with the LeverEvolution bullet. The bullet hit the deer at an angle that should have run in down in and through the chest and out just in front of the opposite shoulder, but instead it bounced off the rib and went up and out the top through the chops just back of the opposite shoulder.
