Rod of Swarming Skulls

An open-mouthed skull caps this thick, onyx rod. The rod has 5 charges and regains 1d4 + 1 expended charges daily at dusk. While holding the rod, you can use an action and expend 1 of the rod's charges to unleash a swarm of miniature spectral blue skulls at a target within 30 feet. The target must make a DC 15 Wisdom saving throw. On a failure, it takes 3d6 psychic damage and becomes paralyzed with fear until the end of its next turn. On a success, it takes half the damage and isn't paralyzed. Creatures that can't be frightened are immune to this effect.