Cave Oracle Nothic

Keen Sight and Hearing. The nothic has advantage on Wisdom (Perception) checks that rely on sight or hearing.

Magic Resistance. The nothic has advantage on saving throws against spells and other magical effects.

Innate Spellcasting. The nothic's innate spellcasting abiliy is Intelligence (spell save DC 16). It can innately cast the following spells, requiring no material components: 

At will: detect thoughts (without using concentration)

3/day each: clairvoyance, dispel magic, fear, mirror image

Nothic Insight: The nothic magically knows the alignment and creature type of any creature it can see within 60 feet of it. 

Reactive. The nothic can take one reaction in every turn in a combat.

Uncanny Knowledge. The nothic gains insight into its opponents, allowing it to make an additional weapon attack as a bonus action if it hits with its claw attack.

Multiattack. The nothic makes two claw attacks.

Claw. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 14 (2d8 + 3) slashing damage.

Rotting Gaze (Recharge 5-6). The nothic targets one creature it can see within 30 feet of it. The target must succeed on a DC 16 Constitution saving throw against this magic or take 35 (10d6) necrotic damage and be cusrsed with a withering gaze. The curse reduces the target's hit point maximum by an amount equal to the damage taken. The reduction lasts until the target finishes a long rest. If a creature's hit point maximum is reduced to 0 by this effect, the creature dies, and its body crumbles to dust.

Fade Into Shadows (1/Day). The nothic becomes invisible until the start of its next turn. While invisible, it can move freely through other creatures and objects as if they were difficult terrain.