That is a great video, Mike! Thanks for sharing. Bull elk can be quite "frisky" during the fall rut. The funniest thing was that the photographer actually was taking shots of the elk when he did not need to protect himself!
I've never had quite that close of an encounter, but once at Yellowstone did have a cow elk sneak up behind me and bugle while I was taking photos of her calf, from what I thought was a safe distance. There was another cow nearby who we thought the calf belonged to. We never saw her before she bugled, and she scared the crap out of us!
I relayed our grizzly bear encounter from last summer in the Glacier Park thread I started in this section. My wife and I were hiking a trail when I walked to within 10-15 feet of a grizzly bear hidden in the brush just off the trail. Luckily, he was more interested in digging for food than us, so we were able to slowly back away. I took this shot after backing off to a safer distance.
We did encounter this bad boy in the parking lot of our lodging at Yellowstone during our last visit. We gave him a wide berth (I was in my car before taking this shot).