Animal Transformation: You have can turn into an alternate animal form. When you transform into a creature you gain the aspect Form of [Animal] and gain all the benefits and drawbacks of that form, e.g. birds can fly, dogs can smell, etc.
When you transform into the animal you gain a single skill at +4 and two skills at +3 that would be relevant to the animal (this may also involve creating a skill, such as Brachiation for a monkey form or Fly for a bird). While in animal form you may use any of the skills from your usual form at -2 (unless that skill is one used by your animal form, then you use the better value).
In order to transform into a creature, you must have the soil (or other material) from the den of the animal. This is done by making a Survival roll against a +2 difficulty to create the aspect Soil from a(n) [animal] den. You may have a number of these aspects equal to your Survival rating. These aspects may be compelled by the GM to change the creature type, representing how multiple animals may have used a den. When you transform into an animal, remove an invocation from the aspect as you use the soil to fuel the transformation. If this is the last invocation, remove the aspect.
Transforming into an animal is an action, however you may also move one zone as part of the transformation.
(Custom, written by Randy. Taken as a blend of existing shapeshifting rules.)