This happened like a few months ago. I was driving westbound on 285, and I passed C470 and was like 300 feet from the Morrison exit. It was late at night, and I saw what I immediately thought was a dog jump out in the road in front of. I looked closer, and it was a mountain lion! It darted across the road, effortlessly leaped over the median, and it "vanished into the night". I was somewhat close to hitting it, but it had to be running at least 20 mph.