This is a crimson glove worn on the dominant hand has embedded rings on the first and second fingers.

Each has a pin protruding from the back of the hand that, when pulled, injects needles into the wearers skin, siphoning off some life force.

This glove converts the users life force into arcane energy. When the pin is pulled (which can be a bonus action), the user takes 1d12 necrotic damage, and regains one spell slot.  Each of the two pins can be pulled once per day. Damage taken this way cannot be healed until the user takes a long rest.

The needles remain embedded until all necrotic damage is healed, only then can the glove be removed.