Blood Star

You create a magic construct called a bloodstar that has
1hp and an AC of 18. You can move the bloodstar anywhere
within range with a bonus action as it floats. The bloodstar
pulses with ruby light providing dim light in a 20-foot radius.
Any creature within 10 feet of the bloodstar that takes
damage from any source must make a Constitution saving
throw against your spel save DC. On a failed save, the victim
takes 2d10 points of necrotic damage. This effect can only
trigger once per round. Keeping control of a blood star takes
up one attunement slot.