You create Horrific Visions when casting harmful spells on enemies. At 50 stacks of Horrific Visions, your target sees a nightmare, dealing 691 Shadow damage and granting you 2 Insanity over 3 sec. At 100 stacks, your target witnesses a vision of N'Zoth, dealing 2,618 Shadow damage and granting you 6 Insanity over 3 sec.