Suffix added to any word to denote that it is a thing of size, power, majesty or grunt, and certainly something to be regarded with awe and reverence. Example: There's not a lot of room in Dan's bedroom, but that's primarily because it contains the Waterbed O'Doom.
O'DOOM
Meaning of O'DOOM in English
Slang English vocab. Английский сленговый словарь. 2012