Belt of the Summoned Lord

Wondrous item, legendary (requires attunement by a fighter or rogue of non-good alignment)

This blood-red belt has countless tiny humanoid skulls sewn into it amid a tentacle pattern engraved with arcane alien runes of chaos and madness.

Radiates: Abjuration, necromancy, transmutation.

Power: You have advantage on saving throws against being charmed or frightened.

Power: You gain resistance to acid and necrotic damage.

Power: You deal an extra 2d6 necrotic damage with your melee attacks.

Power: You gain the gibbering mouther’s aberrant ground trait for 1 minute. You may use this power as a bonus action once per encounter.

Power: You may cast black tentacles once between long rests.

Special: If you are a fighter and use your Action Surge, you may cast fear as a bonus action during your Action Surge.

Curse. Your creature type changes to aberration and aberrations and oozes treat you as friendly unless you or your allies attack them first.