Bloodstone Vengeance Spell
From Multiversal Omnipedia
The Bloodstone Vengeance Spell was a nasty magic spell which Catherine Madison, in the body of her daughter Amy, tried to use against Buffy Summers. According to Giles, the spell "hits the body hard, like drinking a quart of alcohol, then eradicates the immune system." Fortunately, Buffy was able to evade the spell's effects.