Medallion of the necromancer.

This medallion has the shape of human or dragonborn skull, with emeralds at it's eyes.

When you are attuned to this item you gain the following benefits.

Beam of Death. You learn and have always prepared the Eldrich Blast cantrip, and when you cast it it does Necrotic damage instead of Force. 

Summon Dead. As a Bonus Action you can summon 1d6+1 zombies or skeletons. The undead appear in an unnocupied space within 30ft. of you. The undead obey your verbal commands and take their immediately after you. The undead disappear after 10 minutes. Once you do this you can't do this again until the next dawn.

Notes: by a spellcaster.