8-level Necromancy
By using a drop of the target's blood, the caster can control any creature like a puppet. The creature must succeed on a WIS saving throw or fall under the caster's control. The caster can then move the creature however they like, though they cannot make them speak, cast spells or use any special abilities. They could be made to attack someone, walk off a cliff, or choke an ally. The only thing that will break the spell is if the caster's concentration is broken.