Watchers

Watcher in the Water

Gargantuan (long) beast, unaligned

Armor Class tentacle 12, body 16
Hit Points tentacle 23 (3d6 + 12), body 156 (32d8 + 12)
Speed swimming 20 ft.

Damage Resistances bludgeoning
Saving Throws Constitution +7
Condition Immunities blinded, charmed, grappled, poisoned
Skills Perception +3, Stealth +6
Senses blindsight 60 ft., passive Perception 13
Languages unknown
Challenge Rating 8 (3,900 XP)

Grasping Tentacles. The tentacles can reach up to 50 ft. away from the main body.

Multiattack. The watcher may make multiple attacks at once, up to six with tentacles and one with its mouth.

Actions

Tentacle Grab.Melee Weapon Attack: +6 to hit, reach 50 ft., one target. Hit: target is grappled and takes 9 (1d6 + 6) bludgeoning damage each round while grappled (escape DC 15).

Tentacle Smash.Melee Weapon Attack: +8 to hit, reach 50 ft., one target. Hit: 9 (1d6 + 6) bludgeoning damage and target must make a DC 13 Strength saving throw or be knocked prone.

Maw.Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 26 (4d10 + 6) piercing damage.

Lair Actions

On initiative count 20 (losing initiative ties), the watcher takes a lair action to cause one of the following effects; the watcher can't use the same effect two rounds in a row.

Wave Shove. The watcher creates a strong wave that pushes out in all directions from the watcher. All targets in water up to 40 feet away must make a DC 16 Strength saving throw or be knocked prone.

Hurled Scree. Tentacles hurl loose stones and water spray in a 120 ft. cone. All targets in the cone must make a DC 15 Dexterity saving throw (with advantage if they are wearing a shield) or be blinded until the end of their next turn.

Boulder Fall (Recharge 5-6). The watcher smashes and cracks overhanging rocks to fall on a 10 ft. radius area within 60 ft. of the watcher. All targets in the area must make a DC 12 Dexterity saving throw or take 24 (4d12) bludgeoning damage.

Silent Watcher

Large construct, lawful evil

Armor Class 25 (stone body)
Hit Points 94 (14d10 + 10)
Speed 0 ft.

Damage Resistances bludgeoning
Saving Throws Wisdom +9, Constitution +5
Condition Immunities blinded, charmed, deafened, poisoned, prone, restrained
Skills Perception +13, Insight +9
Senses truesight 60 ft, darkvision 1000 ft, passive Perception 23
Languages unknown
Challenge Rating 8 (3,900 XP)

Immobile. The Silent Watcher cannot move.

Otherworldly Perception. The Silent Watcher can sense the presence of any creature within 60 feet of it that is invisible or on the Ethereal Plane. It can pinpoint such a creature that is moving.

Three Heads. The Silent Watcher has advantage on Wisdom (Perception) checks and on saving throws against being frightened, stunned, and knocked unconscious.

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

Innate Spellcasting. The Silent Watcher's innate spellcasting ability is Intelligence (spell save DC 15). It can innately cast the following spells, requiring no components.
At will: detect evil and good, detect magic
5/day each: counterspell as 6th level, dominate person as 6th level, hold person as 6th level
3/day each: bestow curse as 5th level, imprisonment (chains form), hold monster as 6th level
1/day: feeblemind, forbiddance

Actions

Raise Alarm. Alerts all allies within 500 ft.

Frightful Presence. Each creature of the Silent Watcher's choice that is within 60 feet of the Silent Watcher and aware of it must succeed on a DC 16 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to the Silent Watcher's Frightful Presence for the next 24 hours.