Large aberration, typically chaotic evil

Armor Class: 16

Hit Points: 88 16d10

Speed: , can hover

STR

16 +3

DEX

16 +3

CON

11 +0

INT

14 +2

WIS

14 +2

CHA

11 +0

Saving Throws: Int +5, Wis +5

Skills: Perception +5, Stealth +9

Condition Immunities: Frightened

Senses: darkvision 120 ft., passive Perception 15

Languages: --

Challenge Rating: 5

Actions

Multiattack. The feyr makes one Frightful Bite attack and one Tentacle attack.
Frightful Bite. Melee Weapon Attack: +6 to hit, reach 5 ft., one creature. Hit: 8 (1d10 + 3) piercing damage, and each creature within 10 feet of the feyr that can see it must succeed on a DC 13 Wisdom saving throw or be frightened of the feyr until the end of the feyr's next turn. 1d10+3
Tentacle. Melee Weapon Attack: +6 to hit, reach 10 ft., one creature. Hit: 17 (4d6 + 3) psychic damage, and the target is grappled (escape DC 13). Until this grapple ends, the feyr can't use this tentacle against other targets. The feyr has two tentacles, each of which can grapple one creature. 4d6+3
Invisibility. The feyr becomes invisible until it attacks, uses Nightmare Fuel, or uses a bonus action to become visible.

Legendary Actions

Nightmare Fuel (1/Day). The feyr targets one unconscious creature it can see within 10 feet of itself. The target must succeed on a DC 13 Wisdom saving throw or take 27 (5d10) psychic damage, and the feyr gains temporary hit points equal to the damage dealt. 5d10