You cause the cyst created by a blood cyst spell to explode. The creature harboring the cyst takes 6d8 necrotic damage and any creature within 5 feet of it must succeed on a Constitution saving throw or become poisoned for 1 minute. At the end of each of its turns, a poisoned creature can make a new Constitution saving throw. On a success, the spell ends. The cyst created by the blood cyst spell is destroyed, and the creature is no longer considered to be under the effect of a blood cyst spell.