The Thunder Gun is the fourth Wonder Weapon featured in the Nazi Zombie franchise.
The Thunder Gun is a wonder weapon, like the Ray Gun, and is powered also by Element 115. The weapon itself appears to be a compressed air cannon of sorts, but on a much larger scale; and can only be obtained through the randomness of the mystery box.
The Thunder Gun is an excellent weapon when used properly. It is not ideal for taking out individual zombies, but rather large quantites or groups of zombies. It may not always kill on impact, but at the very least will always provide a clear path, free of Nazi foes. It is best used as a secondary weapon used in times of emergency, due to its purpose coupled with its low ammo capacity of 14 rounds total, or 26 when Pack-a-Punched.