Arm of the Great Beyond

You supplicate your Otherwordly Patron to grant you a boon to aid you. One of your arms morphs into a black, twisting tendril that extends beyond your normal reach. For the duration of the spell, or until you dispel it, you cannot wield weapons or shields in your morphed arm, however you can still cast spells as usual. Any items held when your arm morphs, are assimilated within it for the duration of the spell or until you dispel it. Any benefit from items held in your morphed hand are lost until the spell ends.

As part of this spell, you may make an unarmed melee spell attack with your morphed arm at a creature within 15 feet. On a hit, the target takes damage 1d4 psychic and 1d4 bludgeoning damage. Damage made using the morphed arm is magical.

Until the spell ends you may use an action to repeat the melee spell attack.

The morphed arm's damage increases by 1d4 when you reach 5th level (2d4), 11th level (3d4), and 17th level (4d4).