The Tower Cannon is an automated variant of the siege tank.
Structurally, the Tower Cannon is identical to the siege tank. However, it lacks its predecessor's durability, armed only with a weaker variant of the Shock Cannon and incapable of movement. It is also far more vulnerable to damage.
Tower Cannons appear in the bonus map Deception. They are represented by the siege tank, but remain in Siege Mode constantly.