Cannon Carts have no preferred target when attacking; they will simply attack the closest building to them. However, once they become aware of enemy Guard Post troops (either by being attacked themselves or being near another friendly troop under attack), they will leave their previously targeted building and engage the enemy troops instead. Once all of the nearby enemy troops are defeated, they will proceed to attack the nearest building from their current location.
The special ability Last Stand, unlocked at level 2, allows it to continue shooting with temporary hitpoints after its health bar has been depleted, but immobilizes it. The additional health would also slowly deplete. In it's ability it can only shoot in a certain range.
At level 1, the Cannon Cart appears to be a cannon tied to a wooden cart by rope.
At level 5, the Cannon Cart is no longer supported by ropes, and looks like a normal Cannon but with a bigger base.
At level 9, the Cannon Cart now has a bolted ring around its center and looks darker.
At level 13, The center and the last ring of the cart have now turned to gold. It also slightly changes colour.
Of all available Builder Base troops in the game, it has the highest damage per second, disregarding any abilities and damage bonuses.
It is currently the only Builder Base troop that isn't a variant of a Home Village troop, except the Bomber, although it is significant to the Wall Breaker.
The Cannon Cart was added on 22/5/2017 in the game.