AllMovie

While overseeing the atomic tests in the Nevada desert, Army colonel Glenn Manning (Glenn Langan) is exposed to extensive amounts of radiation. As a result, Manning grows, and grows, and grows, at the rate of ten feet per day. This sudden height gain adversely affects the poor man's mind, and soon he's as mad as a hatter. Looking for all the world like Mr. Clean in a diaper, the Colossal Man goes on a murderous rampage, laying waste to numerous landmarks.