Outer Essence Shard (Evil)
Wondrous item, rare (requires attunement by a sorcerer)
- Weight: 1.0 lbs.
This flickering crystal holds the essence of an Outer Plane. As an action, you can attach the shard to a Tiny object (such as a weapon or a piece of jewelry) or detach it. It falls off if your attunement to it ends. You can use the shard as a spellcasting focus while you hold or wear it.
When you use a Metamagic option on a spell while you are holding or wearing the shard, you can use that property.
Property
Choose one creature who takes damage from the spell. That target takes an extra 3d6 necrotic damage.
Source: Tasha’s Cauldron of Everything p. 133