I am planning a new scenario for the DFRPG group that I am GMing, and the upcoming sessions will be some of the first where my PCs will be seriously interacting with a group of shape-shifters who (depending on what my players do) could be either friends or foes.  My question is this: what kinds of catches make sense for were-bears or other shape-shifters with a toughness power?  They are supposed to have one, but I am having trouble figuring out what it is.