Walking Fortress

Animate a Huge or Gargantuan structure, vehicle, siege engine, statue, or mass of connected objects into a mobile fortress. It has AC 20, 200 hit points, a speed of 20 ft., and can carry creatures and objects as appropriate to its form. As a bonus action, you command it to move and make one siege strike for 55 (10d10) bludgeoning damage, or to grant three-quarters cover to creatures of your choice on or behind it until the start of your next turn.