Incomplete Living Armor

To attune, you must wear it for the entire
attunement period, during which tendrils
burrow into you. You have a +1 to AC, and
resistance to necrotic damage.
Symbiotic Nature. This can't be removed
from you and you can't voluntarily end your
attunement. After you finish a long rest, you
must either feed half of your remaining Hit
Dice (rounded up) or 2 lvls of exhaustion.