Ustilagor

Detect Sentience. The ustilagor can sense the presence and location of any creature within 150 feet of it that has an Intelligence of 3 or higher, regardless of interposing barriers, unless the creature is protected by a mind blank spell.

Multiattack. The ustilagor makes one attack with its claws and uses Devour Intellect.

Claws. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 5 (1d4 + 2) slashing damage.

Devour Intellect. The ustilagor targets one creature it can see within 10 feet of it that has a brain. The target must succeed on a DC 12 Intelligence saving throw against this magic or take 9 (2d8) psychic damage. Also on a failure, roll 3d6: If the total equals or exceeds the target’s Intelligence score, that score is reduced to 0. The target is stunned until it regains at least one point of Intelligence.

Body Thief. The ustilagor initiates an Intelligence contest with an incapacitated humanoid within 5 feet of it that isn’t protected by protection of evil and good. If it wins the contest, the ustilagor wriggles into the target’s skull, and takes control of the target’s body. While inside a creature, the ustilagor has total cover against attacks and other effects originating outside its host. The ustilagor retains its Intelligence, Wisdom, and Charisma scores, as well as its understanding of Deep Speech, its telepathy, and its traits. It however does not retain the creature's abilities, and the host uses the appropriate zombie characteristics.

If the host body is destroyed, the ustilagor must leave it. A protection from evil and good spell cast on the body drives the ustilagor out. The ustilagor is also forced out if the target is targetted by a lesser restoration spell, although the intelligence damage remains until healed through a greater restoration spell. By spending 5 feet of its movement, the ustilagor can voluntarily leave the body, teleporting to the nearest unoccupied space within 5 feet of it. The host is then freed of its hold.