I've been blessed to see a lot of wild animals while fishing. Just last Friday I was on my boat working a shoreline when a young weasel walked down to the shore right in front of me. He wasn't full grown, I'd say a "teenager" in weasel years. I've seen a couple weasels while fishing but they usually disappear quickly. This guy or gal stuck with me for a good ten minutes searching the shoreline in the same direction that I was fishing. He stayed a couple feet ahead of my casts and I figured I was fishing old water since he was probably a better fisherman that me.
I'd say the two coolest things I've ever seen on the water weren't while I was fishing, but while my wife and I were feeding fish. We were feeding small fish off a dock at night in Jamaica during stingray mating season. The big males were chasing the smaller males completely out of the water. They would leap out of the water and skip across the surface trying to get away.
The best, however, was two years later in the same spot in Jamaica. My wife and I were on the same dock again which is just about 20 yards from the beginning of the roped-off swimming area. All of the sudden there was a huge commotion in the swimming area in about four feet of water. A 7 to 8ft hammerhead had cruised in and found a big stingray buried on the ocean floor. He gobbled it and slowly cruised back toward deeper water. I wanted to see it closer and I instinctively took off at a full sprint down the dock trying to intercept him while my wife screamed, "Don't you dare jump in! Don't you jump in that water!". The fear in her voice is the only thing that stopped me. I wasn't the least bit scared and I wanted to see that shark, but I wanted to stay married more.
By the way, if we're voting @jbmaine is definitely winning so far. His is absolutely epic.