Question About Smallville??

I'm still watching the episodes. I remember years ago a saw a piece of an episode. It was an ending... and Clark had met a guy and they were running, I think they were outside the barn... soon they were just blurs and it was apparent that Clark couldn't keep up with the guy. They guy then turned and smiled at Clark, and Clark smiled back... and they guy disappeared running beyond the speed of imagining. I thought the guy was played by Jonathan Taylor Thomas, but it couldn't have been him since he played Ian. Who was this guy? Or was I just dreaming? Was it the Flash?