Remote Control

When Rex and Quarry start their battle. Quarry "unwinds" his left arm to use as a mace. When the fight goes to the street Quarry grips Rex with the same left hand /mace. When Rex shakes him off to go into plane mode, Quarry is now gripping him with his right hand (now mace like) as Quarry throws a stop sign with his now normal left arm.Then both arms go back to normal for a few seconds, then Quarry goes back to mace arm attack in the arcade now on right arm. It was shown earlier in episode, he had to physically detach unwind the hand.

Edited from Casablanca (1942)