Infested Cultist's skull

This humanoid skull is infested by a parasitic purple plant from an unknown plane. The longer you stare, the more you could swear that the petals sway in response to an unseen wind.

Forbidden Flower. The skull contains 7 petals. While holding it, you can use an action to pluck a petal to cast the guiding bolt spell (+5 to hit), dealing necrotic damage instead of radiant damage. The skull regrows 1d3 plucked petals daily at dawn. If you pluck the last petal, the skull crumbles to dust and is destroyed.