perhaps it was a cougar.

This sounds a little too much like a Halloween type scary story to frighten kids more than anything else. Let me get this straight, the 7 foot high cat not only "chased him," but couldn't catch him? Large cats can run in excess of 40 to 50 MPH, and probably much faster than that. A child can run what, 8 MPH? Please...

I wouldn't be as skeptical if it wasn't mentioned that he threw things at it and that the thing chased him. He probably saw a large dog in the woods, and after years of thinking about it and his memory/recollection being warped, it turned into a 7-foot high sabretooth tiger. That's just how the mind works.