The Mammoth tank has appeared (in form and function but not necessarily in name) in every C&C game (Command & Conquer 1) except Tiberian Sun (Command & Conquer 2) where it was replaced by a giant, experimental walker (although Mammoth Tanks from the previous war still played a role in the campaign).
Apart from the previous exception, they always took the form of a large tank which was conventional apart from its distinguishing features: twin barrels and four sets of tracks.
They are also characterised by their extreme power, toughness and sluggishness. In a direct, head-on confrontation, they were always the most powerful conventional tank (or ground unit) of their time if not outright the most powerful unit of all.
This is a paper model, it is designed by candcpapercraft, you can download it here:
Command & Conquer 1: Tiberian Dawn - GDI Mammothe Mark I tank free papercraft download