Hard to beat PawPaw's story...
But a couple of years ago I was leaving the woods after chasing whitetails in Northern Idaho. While walking towards my vehicle on an old railroad track that had the ties removed, a big bull moose walked out of the woods about 50 yards from me. Incidentally, I had been standing still looking at some wild turkeys when he stepped out, and he basically walked right on top of them. It scattered the birds pretty quickly.
Anyway, this was early October, towards the late end of the rut, and he made it apparent that he did not like me being there, and immediately charged. There were no trees nearby, except for the ones he just came out of, so the only thing I had to hide behind was my 7mm Mag - which might be a little big to be shooting whitetails with - but it felt pretty darn too small with a moose closing in.
I was slowly walking backwards down the tracks, gun up, not sure what to do, when he stopped at about 20 yards. We stared for a moment or two, then I got the message, and slowly continued to walk backwards toward my vehicle.