My torso. Defying physics as well as biology, while evoking maximum emotional response would be my goal. Yoshi already got head, so I'll have to go with something more over the top. Yes, I would like to be able to snatch my torso right out of its arms and legs configuration, using my teeth in a defiant growl, whipping it at my target like a dog flinging a rabbit to the ground. The regrowth process would start at the severed shoulder of my right arm, and it would sound like churning guts.