The mutant gun turret was an observation tower fitted with a Vulcan cannon. Being an armed civilian structure, it was not very durable, though it was able to blend into the surrounding environment and catch enemies by surprise.
Mutant gun turrets only appear in the Nod mission Sheep's Clothing. They are armed with the same type of weapon as the GDIcomponent tower's Vulcan cannon, but are otherwise identical to the "observation tower" civilian building. They are effective against infantry and light vehicles, but can be easily destroyed by tanks.