You create a tentacle made of blood to attack a creature you can see within range. Make a melee spell attack against the creature. On a hit, it takes 1d4 bludgeoning damage. In addition, choose one creature hit by the spell. That creature must succeed on a Constitution saving throw or take necrotic damage equal to your spellcasting ability modifier and have disadvantage on ability checks until the start of your next turn. At higher levels, the spell creates more tentacles: 2 at 5th level, 3 at 11th level, and 4 at 17th level.