Vampiric Bracers (5e Equipment)
From D&D Wiki
Wondrous item, rare (requires attunement)
Created by a necromancer trying to become immortal these bracers can take and give life.
These bracers when first put on cause 6d6 necrotic damage to the wearer as they attune themselves to the wear by fusing into the skin and connecting to the veins. This is painful to the wearer who will scream like a girl and fall Unconscious, after a short rest the bracers start to regenerate the wearer's health and the wearer wakes up.
Whilst worn, the wearer inflicts an additional 3d6 Necrotic damage in melee combat, and restores hit points equal to the necrotic damage caused in that attack. (And yes a critical hit will double the dice rolled for damage and thus the healing benefit.) Also any body part that is removed or destroyed except the head or heart will regenerate over 1d6+1 days. Arms will grow back with the bracers returning as part of the new arms.
The wearer becomes resistant to Necrotic damage but vulnerable to silvered weapons, sharp wooden stake-like weapons(arrows included) and Radiant damage. Also they now hate garlic.
The bracers can only be removed by the Remove Curse spell or death.