A master chymist's mutagenic form is an alter ego that has a different personality than her normal form, an outgrowth of the mental changes caused by the mutagenic potions she has consumed over the course of her career. The mutagenic form shares memories and basic goals with the chymist's normal personality but goes about meeting those goals in a different manner. The mutagenic form is often ugly and monstrous and may even appear to be a different race or gender than her normal form; they may look as different as two unrelated people. Indeed, the mutagenic form often has his or her own name, and may attempt to maintain independent relationships and strongholds (though the alter ego's limited time in existence often makes this difficult). The mutagenic form even has his or her own alignment (which is selected by the player, but must be different from the master chymist's normal alignment). The change in alignment only affects the master chymist while in her mutagenic form.
Example
Darabont is a neutral good gnome alchemist 7/master chymist 4. Her mutagenic form is a deformed, twisted creature called Butcher. Butcher is neutral, and more interested in seeing the world kept in balance than promoting the greatest good. Butcher is aware she exists only when called on by Darabont, but seeks to build her own circle of like-minded friends during the hours she exists. Butcher does not dislike Darabont, but feels her gnome form is too soft and innocent to survive in the harsh world the chymist lives in. As Darabont, the character detects as good and is affected as a good character by spells with effects that vary by alignment; as Butcher, the same character is neutral, is not revealed by a detect good spell, and is treated as neutral for all spells and effects.