Vesper’s Sèpulcher

  A morbid, purplish-black mist—the cold breath of the tomb—emanates from you. Until the spell ends, any creature that enters the aura for the first time on a turn or starts its turn there must succeed on a Constitution saving throw or take 1d4 necrotic damage.

• Life Tap: The first time a creature fails this save on a turn, you gain Temporary Hit Points equal to the damage rolled. You can gain these Temporary Hit Points several times equal to your Proficiency Bonus, regaining all uses after a Long Rest.

Cantrip Upgrade: The damage increases by 1d4 when you reach 5th level (2d4), 11th level (3d4), and 17th level (4d4).