Ghoul Light

This yellowish-green light is shed by special lanterns; it is a weak glow that discomforts Morwen (inflicting the same penalties as a Continual Light spell) but does not neutralize Infravision. In addition, it reveals invisible creatures or those hiding in shadows within 50 feet. The secret of manufacturing the special oils that create ghoul-light lanterns are closely guarded by the ghoul priests and unknown to other races.