Perfect Beast: Requires Cat form, Dire Bear Form. When used in Cat form, increases armor by 370% and Stamina by 25% for the duration. When used in Bear Form, increases attack power by (Your level*2 + Agility) for the duration. Lasts for 25 seconds. 10 minute cooldown.
Basically, it will give you the benefits of the other form while retaining your current form's benefits. This will be most useful for Feral Tanks that need a threat boost or to finish off a boss, or to help a Cat DPS survive in a sticky situation. It would have to be modified so that the Dire Bear Form version increases your AP by your humanoid form AP and not your Bear Form AP.