I have an animated scene I'm working on where two fantasy characters are fighting and one rips the arm off the other and tosses it away.  What's the best way to go about animating this?  I have the fight done to this point and it looks good, but I'm unsure how to do the arm-rip.  I thought I might just dupe the victim and then make just the duplicate's arm visible and make the arm of the original not visible.  Or is there an easier way?