The bull waited as the hoofsteps retreated down the hallway, waited until he couldn't hear them any longer, then began viciously pulling at his chains.  He grunted, he strained, the tempting hint of freedom before him spurred him on...and yet no amount of flexing would pop a manacle, no degree of tugging would shear the chain.  All his effort merely set him lightly swinging by his wrists.  He closed his eyes and bellowed his fury, before sagging into panting, letting himself recover.