Echo of Demogorgon

Large fiend (demon), Chaotic Evil

Armor Class 14 (natural armor)

Hit Points 85 (10d10 + 30)

Speed 40 ft.

STR 22 (+6)

DEX 10 (+0)

CON 17 (+3)

INT 10 (+0)

WIS 12 (+1)

CHA 14 (+2)

Saving Throws STR +9, CHA +5

Skills Perception +7

Damage Resistances cold, fire, lightning

Condition Immunities charmed, frightened

Senses darkvision 60 ft., passive Perception 17

Languages Abyssal, Giant, Orc

Challenge 6

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

Wakeful. When one of the echo's heads is asleep, its other head is awake.

Actions

Multiattack. The echo makes two Tentacle attacks.

Tentacle. Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 13 (2d6 + 6) bludgeoning damage plus 9 (2d8) necrotic damage.

Bonus Actions

Discordant Screams. The echo directs its frenzied howls at one creature it can see within 60 feet of itself. The target must succeed on a DC 13 Wisdom saving throw or suffer one of the following effects of the echo's choice:

Confused Reaction
The target must use its reaction to make a melee attack against another creature of the echo's choice that the echo can see.
Psychic Torment
The target takes 13 (2d12) psychic damage.

Source

Bigby Presents: Glory of the Giants, p. 132