Stonecloak

Large Construct, Unaligned

AC: 17

Initiative: -1 (9)

HP: 178 (17d10 + 85)

Speed: 30 ft.

STR
22 (+6)
DEX
9 (-1)
CON
20 (+5)
INT
9 (-1)
WIS
11 (+0)
CHA
9 (-1)

Immunities: poison; psychic; bludgeoning, piercing, slashing from nonmagical attacks that aren't adamantine

Condition Immunities: charmed; exhaustion; frightened; paralyzed; petrified; poisoned

Senses: darkvision 120 ft., Passive Perception 10

Languages: understands Abyssal, Celestial, Common, Draconic, Dwarvish, Elvish, Infernal, and Undercommon but can't speak

CR: 10 (XP 5,900; PB +4)

Immutable Form.

The stonecloak is immune to any spell or effect that would alter its form.

Magic Resistance.

The stonecloak has advantage on saving throws against spells and other magical effects.

Magic Weapons.

The stonecloak's weapon attacks are magical.

Actions

Multiattack.

The stonecloak makes two slam attacks.

Slam.

Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 19 (3d8 + 6) bludgeoning damage.

Slow (Recharge 5-6).

The stonecloak targets one or more creatures it can see within 10 feet of it. Each target must make a DC 17 Wisdom saving throw against this magic. On a failed save, a target can't use reactions, its speed is halved, and it can't make more than one attack on its turn. In addition, the target can take either an action or a bonus action on its turn, not both. These effects last for 1 minute. A target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

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Stonecloak

Source: Waterdeep: Dungeon of the Mad Mage, p. 253 - Licenses and attribution