Mangonels will inflict 4 damage against a random Civic, Artistic or Holy card on the opponent's field as long as they have no active Fortified cards in play. If there are no active Fortified at the time of purchase, it will immediately apply the damage. If there are, it will not activate until the Fortified have been knocked out. This ability will only activate once per round.
Mangonels, derived from the Greek mágganon, meaning "engine of war", is what many people think of when they picture a catapult. It consists of a long wood arm at a 90° angle with a bucket with a rope attached to the end. The arm is pulled back, energy storing in the tension of the rope and the arm. When released, the arm would return to its equilibrium position, launching the ammo placed in the bucket toward the enemy. Ammo usually consisted of rocks, though anything could be used, including dead and diseased animals and people.