Report 1271: Six foot tall or taller, black creature was observed leaping into the air and disappearing into the trees on a bike trail near the Des Moines River

I heard the deer coming toward me over to my left. I was going down the trail and the deer was coming in the opposite direction about a hundred feet over to my left. He kept looking over his right shoulder at something. I wondered what he was looking at and I lifted my head a little and that is when I saw the thing. At first I thought it was a human being. I mean it had a head, shoulders, arms and legs, chest. It saw me at a distance of about three hundred feet and when it saw me it kind of hunkered down. I have seen deer do the same sort of thing when they are preparing to take flight. After hunkering down, it made a 90 degree turn and leaped and bounded through the air. Both feet were off the ground. It made another 90 degree left turn and disappeared among the trees. I could see the blackness disappearing behind and among the trees as it left. The total viewing time was no more than 3 seconds. It left in a big hurry. It was tall, about 6 feet or a little taller, black, slim and quick. I mean it was quicker than a deer. Imagine an Olympic class sprinter cooking off a hundred yard dash. Multiply that quickness by a factor of 2 or 3. It was incredibly quick, quicker than a deer.