The Shimmering Shade Beneath the Hollow Waves

An eerie silhouette emerges from the depths of a tranquil water surface, its form shifting like a mirage. This creature glimmers with a phantom light, reflecting eerie colors that play tricks on the eye. It embodies the essence of both water and shadow, slipping effortlessly between dimensions. When it strikes, its touch not only inflicts physical harm but also entangles the victim's senses, causing disorientation and confusion. Those who encounter this ambiguous entity find themselves grappling with unsettling visions that linger long after the battle has ended.


Medium Aberration, Chaotic Evil

Armor Class 15 (natural armor)
Hit Points 92 (13d8 + 39)
Speed 0 ft., swim 60 ft.

STR DEX CON INT WIS CHA
14 (+2) 20 (+5) 16 (+3) 4 (-3) 12 (+1) 18 (+4)

Saving Throws Dex +8, Con +6, Wis +4, Cha +7
Skills Stealth +11, Perception +7, Deception +10
Damage Immunities psychic, poison
Condition Immunities charmed, frightened, paralyzed
Senses darkvision 60 ft., passive Perception 17
Languages understands Aquan and Common but cannot speak
Challenge 6 (2,300 XP)

Proficiency Bonus +3

Ethereal Vision. The creature can see 60 feet into the Ethereal Plane when it is on the Material Plane, and vice versa.

Shapechanger. As an action, the creature can polymorph into a shadowy form or back into its true form. While in shadow form, it gains resistance to all damage except force and radiant.

Shadowy Encounter (Recharge 5-6). The creature can create an illusion of itself in an unoccupied space within 30 feet that lasts for 1 minute. The illusion has the same statistics as the creature but cannot attack. Any creature that starts its turn within 20 feet of the illusion must succeed on a DC 15 Wisdom saving throw or become frightened until the end of its next turn. The illusion can be dismissed as a bonus action by the creature.

Actions

Multiattack. The creature makes two tentacle attacks.

Tentacle. Melee Weapon Attack: +8 to hit, reach 15 ft., one target. Hit: 15 (2d10 + 4) necrotic damage. The target must make a DC 15 Constitution saving throw, taking an additional 10 (3d6) psychic damage on a failed save, or half as much damage on a successful one.

Phantasmal Wave (Recharge 5-6). The creature unleashes a wave of phantasmal energy in a 30-foot cone. Each creature in that area must succeed on a DC 15 Intelligence saving throw or take 27 (6d8) psychic damage and be incapacitated until the end of its next turn. A successful save results in half damage and no incapacitation.

Reactions

Evasive Retreat. When the creature takes damage, it can teleport up to 30 feet to an unoccupied space it can see, reappearing in its shadowy form before the damage is applied.