What happens when your character with Voluntary Shapeshifting begins to suffer Sanity Slippage? You get a Shapeshifter Identity Crisis, which is the sometimes non-lethal sibling to Shapeshifter Swan Song, and the polar opposite of Shapeshifter Mode Lock. May be triggered as a result of Becoming the Mask, or may result in Becoming the Mask if you have a Manipulative Bastard guiding the person back from the crisis point. It can also be due to The Mind Is a Plaything of the Body, as having many different forms can make determining which one is the "real you" a bit more difficult.