Dubbed “North America’s Loch Ness Monster,” the purported leviathan of Lake Champlain, “Champ,” has just resurfaced. On Feb. 22, 2006, Good Morning America aired exclusive video footage of “something” just below the surface of the water, possibly the lake’s fabled creature. A pair of Vermont men, Dick Affolter and his 34-year-old stepson, Pete Bodette, had made the digital recordings the previous summer while salmon fishing. ABC consulted two retired FBI forensic image analysts, who concluded that the video appeared authentic, although they could not say what it depicted. The incident added to a long list of Champ sightings, which...