On a successful save, the target isn’t affected, and you can’t use this spell against it again for 24 hours.
On a failed save, the spell creates an invisible sensor within 10 feet of the target. You can see and hear through the sensor as if you w ere there. The sensor moves with the target, remaining within 10 feet of it for the duration. A creature that can see invisible objects sees the sensor as a luminous orb about the size of your fist