Or, they could grab the floating head that's left of you and store it in a jar for poops and giggles. O__o
But that is certainly a creative way of dodging harm. You know how some folks go intangible to avoid an attack or something. Let's say your foot has been hit with Dexter's chalk, and it's starting to devour your flesh. You could use your costs to force that part of your body to vanish, meaning the chalk has nothing to chew on.
Now that, milady, is cunning!
That might work with Dexter, since he usually stays at the Dionysus Sequoias, but Wilma tends to attack anywhere without so much as a warning...