Watch 123Movies. Thunderbeast is a stunning insiders view of one of our country's most impressive wild creatures-the American buffalo. Working over a period of eight years, Emmy-award-winning wildlife filmmaker Bob Landis documented the real dramas of bison in Yellowstone National Park. From epic battles with grizzly bears and wolves, treacherous winters to late summer mating season, Thunderbeast captures the awesome survival skills of this American icon.