Buck Brawl.

When watching videos like this I honestly get nervous they are going to kill each other.
I've not SEEN a heavy-duty fight, but I HEARD one at night in a remote mountain area. I had stayed in my tree stand past dark to let some deer get past me and out to a field without spooking them. I heard two deer stomping toward each other from different directions. BIG fight broke out. After about 5 min. they separated and I heard a little running - then smash again! Another separation - lots of panting & grunting - then running and THUMP! and the sound of the air getting knocked out of one of them. I'm sure one t-boned the other and gored it. The loser took off like his tail was on fire. The winner walked around the area for about 15 min. stomping & grunting as if to say " I'm ready for all comers ".
I stayed in the tree for about another hour until I heard him take off after a doe. I wasn't coming down until I knew he left the area.