Here's another version of shapeshifting I used in one Amber campaign. It's a slightly more detailed version than in my Chaotic Vs Orderly Shapeshifting post, but it's slightly less elegant as a result.
Dynamic Form: 5 Points
You may have from 2 to 12 forms, your choice. More forms allows great versatility, but at the cost of individual forms being weaker.
Dynamic Form is the base Power of Chaos. It’s unpredictable and uncontrollable, but most of the shapes should be surreal or mythological. Think Salvador Dali, Hieronymous Bosch, HR Gieger, and Grimm’s Fairytales. A goat-headed man, a faceless witch, and a shadowy hound are far better Forms than a potted petunia, a salad fork and a killer virus.
Also note that there are no normal humans in Chaos - everyone is a bit distorted and sinister out at the end of the Universe.
Each form must have at least 1 Trigger (see below) and some of your forms will have special bonus Qualities, similar to those on the Artifact & Creature Worksheet. In addition, one of your forms must be designated as your True Form, the others become designated as Alternate Forms.. Full details can be found below.
Triggers: A Trigger is the circumstance that causes you to assume a given form. Most Triggers fall into one of the following categories:
Chemical Trigger: An allergic reaction to certain substances causes you to take this form.
Emotional Trigger: There is a particular emotion that causes you to take this form.
Celestial Trigger: Certain astological or meteorlogical circumstances will cause you to take this form.
Power Trigger: Exposure to (or the use of) a certain power causes you to take this form.
Karmic Trigger: Count on your Good Stuff or Bad Stuff to put you in this form at the dramatically appropriate moment.
* It is important to note that free choice is not a possible Trigger. That is to say the Dynamic Form Power does not allow you to merely shift from shape to shape as you see fit. It is beyond your power to totally control this gift.
3 examples of Chemical Triggers, drawn from films, novels, comics or RPGs....
1)The werewolf who reverts to human form when struck by silver.
2)The vampire who becomes a ferocious monster when they taste blood, but becomes a cowering wretch at the scent of garlic.
3) The scrawny little sailor who fights to the finish when he eats his spinach.
3 examples of Emotional Triggers, drawn from films, novels, comics or RPGs....
1) The irradiated scientist who turns green and bulky whenever someone hurts him.
2) The Viking Berserker who works himself into a rage and becomes a rabid bear.
3) The research subject whose alien-engineered DNA only makes itself pronounced when they are frightened or sexually aroused.
3 examples of Celestial Triggers, drawn from films, novels, comics or RPGs....
1) The werewolf whose form is dictated by the phase of the moon.
2) The alien hero who becomes able to leap tall buildings when transplanted to a world with a different-colored sun.
3) The demon who shows his horns, hooves and tail only when back in the damnable environs of hell, but looks like any other Lawyer when on earth.
True Form: The form you were born in has all your normal Attributes and Powers, but no bonus qualities at all. Your True Form has two default triggers, listed here:
Death/Incapacitation: In the case of Death or Paralysis, or should your soul leave your body, your body will return to your True Form.
Order Exposure: Advanced Pattern and certain Power Words can be used by others to make you take your True Form.
You must create at least 1 extra trigger that returns your character to their True Form.
Bonus Qualities: Individual forms may integrate Qualities from the Artifact & Creature Worksheet. You may select up to 8 points of Qualities from that worksheet, with these restrictions:
1) Your True Form may not have any Qualities, it uses just your normal stats.
2) Each Form may have 0 to 3 points of Qualities, up to 8 Qualities total between all your Forms.