Slough

Transmutation [evil]
Level: Cleric */Oracle * 5, Sorcerer */Wizard * 5, Warlock * 5
Components: V, S, M/DF (a pinch of dried skin flakes)
Casting Time: 1 Standard Action
Range: medium (100 ft. + 10 ft./level)
Target: one living creature
Duration: instantaneous
Saving Throw: Fortitude negates
Spell Resistance: yes
  The target takes 1d4 points of Constitution damage each round as its skin loosens and splits. Once it has taken 5 or more points of Constitution damage in this way, its skin falls off to reveal its musculature. The creature ceases taking Constitution damage, but takes a -4 penalty on saving throws against disease, pain effects, or poison, and on Charisma-based skill checks with the exception of Intimidate and Use Magic Device. The creature's skin regrows rapidly-once its Constitution damage is fully healed, its skin becomes intact once again and the penalties end.