The witch can augment her familiar, making it grow into a larger "combat form." The combat form is identical to a druid's animal companion (using the character's witch level as her druid level). The combat form of the familiar should be written up as an animal companion with a similar physical form or special abilities (a cat animal familiar should use the big cat animal companion for its combat form, while the fox uses a wolf animal companion and a centipede familiar uses a viper).
The witch can change her familiar from its normal form to its combat form or back as a standard action. Damage taken in one form does not carry over to the other. When the witch rests and prepares her spells for the day, all damage on her familiar's combat form is healed. If her familiar dies in either form, it remains dead in the alternate form.
While in combat form, the familiar functions in all ways as an animal companion, and it does not retain any of its special abilities as a witch's familiar. (While her familiar is in combat form, a witch can cast spells she has already prepared, but can not prepare spells stored within her familiar until it regains its normal form.) The familiar can maintain its combat form for a maximum of 1 minute per level of the witch. These minutes do not need to be consecutive, but they must be spent in 1-minute increments.
