Black Horn of Orcus

Cursed. This dark black horn is one of a pair from the demon Orcus, and is indestructible. The rest of him sure wasn't.

Any creature that touches the horn must immediately make a DC 30 Wisdom Saving Throw or be possessed by the Horn's dark powers. If the bearer resists the possession, they take 5d10 Cold damage and 5d10 Necrotic damage at the end of every turn it holds the horn.
The dark symbol of Orcus appears on your forehead. At your command, you may summon the Horn to appear or disappear from your forehead. While the Horn is active, you receive the following traits:

• Once per turn you may deal an additional 1d12 Necrotic damage to your damage roll.
• Resistance to Necrotic damage.
• Vulnerability to Radiant damage.
• Read, Speak, Write, Comprehend: Infernal and Abyssal.
• At the start of each of your turns, all creatures within 10ft of the bearer take 1d10 Cold damage.
• You can cast Speak With Dead 1x/Day without expending a Spell Slot. This ability recharges at Dawn.
• You can use the power of the Horn of Orcus to twist the minds of other creatures, causing them to lose their grip on sanity. 1x/Day as an Action, you may attempt to force a creature within 60ft that you can see to madness. The target must succeed on a DC 15 Wisdom Saving Throw or be forced to roll a 1d100 on the Short-Term Madness chart.
  • When the bearer uses this feature, they must also succeed on a DC 15 Wisdom Saving Throw or be forced to roll a 1d100 on the Long-Term Madness chart.