Lt. Col. Glenn Manning is the central character of the movies The Amazing Colossal Man and War of the Colossal Beast, featured in Season 3 of Mystery Science Theater 3000. Manning, participating in a nuclear test at the beginning of the first movie, is irradiated and grows to the height of 60 feet.
In The Amazing Colossal Man, Manning is portrayed by Glenn Langan (credited as Glen Langan). In War of the Colossal Beast, Manning (who is disfigured and unable to speak) is portrayed by Duncan "Dean" Parkin.
In both his of MST3K segment appearances, Michael J. Nelson plays Glenn. He is ostensibly taller than 60 feet, as he is able to reach and interact with the Satellite of Love.