The Compendium of Caraka 2.7.12

2.7.12

In that regard, this is the particular manner of onset of the spirits that produce insanity when they are about to drive one insane; namely: the gods cause insanity by gazing, gurus, elders, siddhas, and great sages by cursing, the pitṛs by showing themselves, the gandharvas by touching, the yakṣas by entering into, the rākṣasas by making one smell their own odor, and the piśācas by mounting and riding.