A skeleton reanimated by the illithilich Scelerus
the Abhorrent. Many are actually several halfling skeletons assembled into a large amalgam, and all of the skulls have a large whole in the front cranium.
Multiattack: The skeleton makes two melee attacks.
Scimitar: +4 hit, 1d6+9 slashing damage.
Shortbow: +4 hit, range 8-/320 ft., 1d6+9 piercing
Spell Immunity: Immune to Thunderwave, Lightning Bolt, and Heat Metal.
Multiattack: The helmed horror makes two longsword attacks.
Longsword: +6 hit, 1d8+4 slashing damage. This weapon is made from adamantine.
Sneak Attack (2d6).
Illithid Infiltrator: This creature is possessed by an intellect devourer.
Sentience (300 feet, Int 3 or higher).
Multiattack: The infiltrator makes two melee attacks.
Scimitar: +5 hit, 1d6+3 slashing damage.
Hand crossbow: +5 hit, 30/120 ft. range,
Detect Sentience (300 ft., Int 3 or higher).
Claws: +4 hit, 2d4+2 slashing damage.
Devour Intellect: One target, DC 12 Int save or take 2d10 psychic damage, and roll 3d6. If the 3d6 meets or beats the target's Int score, their Int is reduced to 0 and Stunned until they regain at least 1 Int.
Body Thief: Int contest vs. target. If the intellect devourer wins, it devours the targets brain and teleports into its cranium, possessing its body and absorbing its memories. For more details, see pg. 191 of the Monster Manual.
A souvenir that Scelerus took from the Silver City, Anubiek is the name the Indarians gave to the neothelid that serves as the illithilich's living phylactery.
Creature Sense (1 mile, Int 4 or higher).
Gibbering Souls: Anubiek constantly emits a miasma of psychic detritus formed from the countless souls it has devoured. Whenever a creature starts its turn within 120 feet of Anubiek, it must make a DC 16 Wis save. On a failed save, it can't take reactions until the start of its next turn and rolls a d8 on its turn to determine what it does. 1-4: it does nothing. 5-6: no action or bonus action, and it moves in a random direction. 7-8: melee attack against a random creature, or nothing.
Soul Release: Whenever Anubiek takes 15 or more damage on a single turn, a fragment of a devoured soul is released in the form of a specter, The specter has its own Initiative, serves Anubiek, and is reabsorbed in 1 hour unless it is destroyed.
Tentacles: +13 hit, 15 ft. reach, 3d8+8 bludgeoning damage plus 3d8 psychic damage. Large or smaller creatures must make a DC 18 Str save or be swallowed (10d6 force damage at the start of Anubiek's turns). If Anubiek takes 30 or more damage from a swallowed creature in a single turn, it must make a DC 18 Con save or regurgitate all swallowed creatures, which land prone within 10 feet of it. If a creature dies while swallowed, it is devoured body and soul by the living phylactery.
Force Breath (recharge 5-6): 60-foot cone. DC 18 Con save. 10d6 force damage on a failed save, half on a success.
Innate Spellcasting (Psionics, Wis-based, DC 16).
--At will: Levitate.
--1/Day each: Confusion, Feeblemind, Telekinesis