"The Sheikah of ancient Hyrule developed this as a weapon to combat Ganon. This stationary model was used for defending important structures. Its offensive power is on par with other Guardians, and omitting the legs kept the manufacturing costs low."
Hyrule Compendium

Guardian Turrets are enemies in The Legend of Zelda: Breath of the Wild. They are a type of Guardians found only in Hyrule Castle and behave identically to Decayed Guardians, only with more health and vertical range by deploying its head upwards. The Guardian Turret has a similar design to the Beamos in Skyward Sword.