Unerring Sentry

You conjure an arcane sentry in an unoccupied space that you can see within range. It can take any form you wish, but is obviously magical in nature, and is always Small or Medium. It lasts for the duration, until you dismiss it, until you move 100 feet from it, or until you cast the spell again.

When you cast the spell, designate any number of creatures you can see as the sentry’s allies. The sentry is invisible to everyone except its allies, and if any other creature of challenge rating 1/4 or higher comes within 60 feet of it, it calls out an alarm. It can see invisible creatures, see into the Ethereal Plane, and cannot be deceived by illusions.

As an action on your turn, you may direct the sentry to attack a target you can see within 100 feet of its original location. It can move up to 30 feet, and attack a creature within 5 feet of it. Make a melee spell attack. On a hit, it deals 4d8 force damage. If you are incapacitated, unconscious, or otherwise unable to direct the sentry, then at the end of your turn it attacks the nearest creature of challenge rating 1/4 or higher that is not its ally.