This starts from the closest limb to the target point on the body and spreads from there (if no specific target, choose a limb randomly). Use the damage required to cripple the limb to measure progress of the effect.

For example, this starts from the arm of a victim with 12 HP. After 3 HP, his hand is crippled. After 6 HP, his arm is crippled. After that, it spreads to the torso and stopping it gets far more difficult.

Ghoulish Transformation [133] 
    Innate Attack (Toxic) 0d+1 [110.55] 
        Malediction (As Regular Spell) [+100%] 
        Based on Activation Roll [+5%] 
        Cyclic (109 Cycles at 1 Second Intervals) [+10900%] 
            May be stopped by surgically removing the affected flesh 
                Usually can't be accomplished without inflicting more damage 
            May also be stopped by healing all of the damage dealt in one pass 
                Healing in multiple passes and then curing disease (-3 penalty) 
                    will also work 
        Spreads from Closest Limb First [-10%] 
            Closest to target point; allows for an early, simple amputation 
    Dominance [22] 
        Victim Must Die [+0%] 
        Cosmic (Victim Becomes a Ghoul) [+50%] 
    Magical [-10%] 
    Spell Components [-30%] 
        Must say "ghoul" in Latin 
        Must gesture with hands 
        Must hold a fingernail from a corpse and a pinch of mandrake root 

• Ghoul.gct