Medium Fiend, Chaotic Evil
Armor Class 15 natural armor
Hit Points 22 (4d8 + 4)
Speed 35 ft.
STR
9 (-1)
DEX
11 (+0)
CON
6 (-2)
INT
16 (+3)
WIS
8 (-1)
CHA
4 (-3)
Saving Throws INT +5
Skills Stealth +17
Damage Vulnerabilities Lightning
Damage Resistances Fire
Senses Passive Perception 19
Languages --
Challenge 1 (200 XP)
Proficiency Bonus +2
Traits

All Seeing Eye. The watcher cannot be hit with sneak attacks and has advantage on intelligence checks.

Opportunity Strike. When attacking if no player allies are within 10ft. of the player that player takes an extra 2d4 damage on a successful hit

Compelling Stare. Once within 35ft  of the watcher players must make a 16 perception check in order to move out of its range

Actions

Fierce Charge. Melee Weapon Attack: +5 to hit, reach 5 ft., 1 target. Hit:  1(2d6 + 3) [physical] damage. 

Scalding Blood (Recharge 2). Ranged Weapon Attack: +6 to hit, range 10/35 ft., 1 target. Hit:  1(3d4 + 8) [acid] damage.

Bonus Actions

Haunting Vision. If there is a player within 40 feet of the watcher and the watcher has a clear sight line of the player, that player makes a 15 constitution saving throw. On a failed throw players are paralyzed 

Reactions

Tactical Retreat. When hit by an attack the watcher can retreat up to 10ft.

Nightmarish Resolution. When the watcher is defeated using bludgeoning, slicing or piercing damage each player within a 20 ft. radius makes a 13 constitution saving roll, players that fail the save take 2d6 fire damage, in addition  2 + 1(for each party member) dream parasites are spawned upon its defeat.

Description

The Watcher is a terrifying eldritch beast that wanders the night stalking its prey while staying just out of sight. The Watcher's action are calculated, waiting as long as needed to catch an unsuspecting party member with its paralyzing vision. While not the most durable foe, many adventurers would argue that the part that comes after is even more terrifying. 

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