Perturabo, Lord of the Cage

When Perturabo, Lord of the Cage enters the battlefield, each noncreature artifact you control becomes a 0/5 Wall creature with defender.
As long as you control a Wall, Perturabo has indestructible and can't be returned to the hand
or put into your library from the battlefield.
Sacrifice an artifact creature with defender:
Perturabo fights another target creature.