See Shapechangers

3nd-level divination

Classes: bard, cleric, druid, paladin, ranger, legendary shaman, sorcerer, warlock, wizard

Casting Time: 1 action

Range: self

Components: V, S, M (ointment of honey and lotus petals, applied to the eyelids)

Duration: Concentration, up to 1 minute

You gain advantage on Wisdom (Perception) ability checks to spot shapechangers and ability checks to identify them and their abilities. In addition, as a bonus action, you can examine any creature within 60 feet and determine whether it is using an effect to change its true form and what its true form is. If the target is a shapechanger but is already in its true form, this divination identifies that it is a shapechanger but cannot determine what other forms it might be able to assume unless you succeed on an ability check to identify the creature.