This paper model is a Terran Siege Tank (Tank Mode), a terran vehicle that can be configured to fulfill both the armored support and the long-range artillery support roles, based on the military sci-fi real-time strategy game StarCraft II, the papercraft is created by Dennis Grieshermer. There is also a Sige Mode Version on the site available.
The siege tank provides the terrans with mobile, long range firepower. The siege tank continues to function as it did in previous games with the dual tank and artillery modes, except it doesn't require as much support as is needed in the original StarCraft. The tank cannot fire when moving, leaving the tank vulnerable to attacks by melee units. It is also highly vulnerable to air units.
The siege tank bobs slightly when it stops moving. Siege tanks are strong against marines and hydralisks, and weak against thors, immortals, and zerglings. Given its firepower, siege tanks are also popular with marines and marauders, providing artillery support for both defensive and offensive roles. When combined with the MMM combo, it is especially effective against roaches, stalkers and even deterring colossi to an extent. [Source: wikia]
You can download the papercraft model template here: StarCraft II - Terran Siege Tank Ver.2 Free Paper Model Download