Choose two creatures you can see within range. The targets must make a Constitution saving throw.

On a success of one or both targets, the creatures are unaffected. If both targets fail the save, then then a strand of necrotic energy creates a blood bond between these creatures, making them susceptible to damage whenever the other member of their blood bond is damaged. While within 60 ft of each other, if one creature in the blood bond takes damage then the other creature equal to the damage taken plus your ability modifier, as necrotic damage.

If both targets are subjected to an effect, such as an AOE spell, that causes both to take damage, the creatures as still damaged in this way. If the targets move more than 60 ft apart, then they are temporarily unaffected by this spell, but may be affected again if they move back into range during the duration.