Echani Art

If a humanoid you can see makes a melee weapon attack, you can use your reaction to make a Wisdom (Insight) check against the target's Charisma (Deception). On a success you learn one of the following traits about that creature: it's Strength, Dexterity or Constitution score; bonus to Strength, Dexterity or Constitution saving throws; armor class; or current hit points. On a failure, the target becomes immune to this feature for one day. You can use this ability a number of times equal to your Wisdom modifier (a minimum of once). You regain all expended uses on a long rest.