Heliana's Guide to Monster Hunting, pg. 501
1st ring Wyrd, Enchantment
You float some mildly distracting thoughts into the mind of a humanoid you can see within range. The target must succeed on a Wisdom saving throw or have disadvantage on Wisdom (Perception) checks (taking a -5 penalty to its passive Perception as a result of this disadvantage) until the spell ends. A creature immune to being charmed is unaffected by this spell.
A creature that succeeds on the saving throw by 5 or more is aware that an attempt was made to influence it with magic. Otherwise, the creature remains unaware of the magic that affected it.