Something like this?
Ravenous Breath (Su): Once every 1d4 rounds, the Great Wendigo can breath a 60 ft cone (??) that does 8d12 cold damage. A DC X Reflex save halves the damage. In addition, any creature damaged by the breath weapon must make a DC X Will save or become ravenous. On a failed save, the victim must immediately attack the nearest sentient creature; if the victim successfully kills its target, it will cease all other activities to eat its target.