For flavor players roll 1d100 at creation of character (roll twice if Psionic, Shadow, or Arcane power source class).
On a result of 1-25 you have no physical mutations from the chaos tainted world. You can even remove the Spellscarred feature from your character sheet in Character Builder.
On a roll of 26-94 you have a physically detectable mutation that doesn’t affect play. You can use your imagination here to add flavor to your appearance.
On a roll of 95-99 you can design a mutation that gives you a +1 to any specific roll or effect as well a visible mutation to your body. The mutation’s mechanics requires DM approval.
On the roll of a 100 you can create a mutation that gives you an encounter or daily power equal to a racial power. I recommend you use existing racial from any race as a template. I have final say, but please push the envelope and develop something creative. The mutation’s mechanics requires DM approval.