Greater Ghoul Bite

Because you were taken to 0 hit points by a Greater Ghoul they have left a remanent of the necromantic essences that has molded them into the form they now take. 

once a day make a DC 15 con check. On a success you are unaffected but the DC of the check increase by 1 for the next day.  If you fail you attack the nearest living thing until it is dead and you feast upon its flesh. 

In combat when an enemy or ally is bloodied (Health is at half) roll a DC 17 con check. On a success you resist the urge on a failure you attack the bloodied creature until it is dead and you feast upon its flesh. 

After the 5th time you consume the flesh of someone that you have attacked you transform into a ghoul and are considered dead.