Boil Blood (5e Spell)
From D&D Wiki
|Casting time:||1 action|
|Duration:||Concentration, up to 1 minute|
You point your finger at a creature you can see within range, and its blood begins to boil. The target must succeed on a Constitution saving throw, taking your choice of 8d10 fire or necrotic damage on a failed save. As an action on each of your turns, you can force the target to repeat the saving throw. On a success, it takes no damage this turn. On a failure, it takes the spell's damage again. This spell has no effect on undead or constructs.