Plague

This spell inflicts a virulent, infectious disease on any single creature (if a saving throw vs. spell is failed). The creature immediately suffers an attack of plague, becoming feverish and disoriented with illness for a full hour. During this time, the creature loses 10% of its original hit points, 1 point each of Strength and Constitution (if these are known), has -2 penalties to saving throws, attack, and damage rolls, and a +2 penalty to Armor Class.

All creatures within 10 feet of the creature must make a Constitution check or contract the plague themselves (with the same effects). Creatures currently suffering from the plague cannot contract multiple cases of it, and those within range of more than one affected creature need only check once.

When the spell effect expires, the creature is no longer infectious and the penalties end, except that lost hit points and ability scores take 1d6 days to return. Before the last of the plague's effects wear off, a final Constitution check must be made; if the creature rolls a natural 1 on a 1d20 roll, it dies.

The material component is a glass flask of rat viscera bathed in a small quantity of body fluids from plague victims.