Ball of Spiders

Magic item.

(Uncommon)

A black, palm-sized ball with faintly writhing patterns etched into its surface. Action: Throw this ball up to 6 spaces. Upon impact, it shatters, releasing a swarm of harmless but horrifyingly realistic spectral spiders that cover a 2x2 area. Creatures in the area must make a WIL save or be Frightened until the end of their next turn. Once used, the ball reforms at the next Safe Rest.

From Core Rules