Glimpse of Darkness - D&D5e (Patreon)

Wondrous item, very rare

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This bomb was first crafted by a powerful sorcerer to unleash the power of the Shadow Realm upon the battlefield. With a single detonation, it tears a hole in the fabric of reality and summons forth a fragment of the realm of shadows itself, unleashing its dark and twisted magic upon the mortal world.

The air grows thick and heavy, and a profound silence descends, broken only by the sound of one's own heartbeat. It's as if the world itself has been swallowed by an endless void, where even light cannot escape. A 20-foot area around the bomb becomes engulfed in magic darkness, and no sound or nonmagical light can be created within or pass through the area.

Within the rift, shadowy tendrils writhe and lash out, seeking to ensnare and drain the life force of any living creature. All creatures that are in the area when the bomb goes off, that enter the area for the first time each turn, or that end their turns there must succeed on a DC16 Dexterity saving throw or become grappled and restrained by the tendrils.

A creature can use its action to make a DC16 strength saving throw to attempt to free itself or attempt to strike the tendrils. Each tendril has AC 15 and 30 hit points. They are immune to bludgeoning, piercing, and slashing damage from nonmagical weapons and vulnerable to radiant damage. The longer one remains grappled by the shadowy tendrils the more it drains the creature’s life force. At the start of each of its turns, a grappled creature takes 3d6 necrotic damage.

The effect lasts for 1 minute, after that the darkness slowly dissipates and the tendrils disappear.