Breaker Beast

Detect Sentience. The breaker beast can sense the presence and location of any creature within 300 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.

Iron Scent. The breaker beast can pinpoint, by scent, the location of ferrous metal within 30 feet of it.

Rust Metal. Any nonmagical weapon made of metal that hits the breaker beast corrodes. After dealing damage, the weapon takes a permanent and cumulative −1 penalty to damage rolls. If its penalty drops to −5, the weapon is destroyed. Nonmagical ammunition made of metal that hits the breaker beast is destroyed after dealing damage.

Multiattack. The breaker beast makes one attack with either its claws or its antennae and uses Devour Intellect.

Claws. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 7 (2d4 + 2) slashing damage.

Devour Intellect. The breaker beast targets one creature it can see within 10 feet of it that has a brain. The target must succeed on a DC 13 Intelligence saving throw against this magic or take 11 (2d10) 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 breaker beast initiates an Intelligence contest with an incapacitated humanoid within 5 feet of it that isn’t protected by protection from evil and good. If it wins the contest, the breaker beast magically consumes the target’s brain, teleports into the target’s skull, and takes control of the target’s body. While inside a creature, the breaker beast has total cover against attacks and other effects originating outside its host. The breaker beast retains its Intelligence, Wisdom, and Charisma scores, as well as its understanding of Deep Speech, its telepathy, and its traits. It otherwise adopts the target’s statistics. It knows everything the creature knew, including spells and languages.

If the host body dies, the breaker beast must leave it. A protection from evil and good spell cast on the body drives the breaker beast out. The breaker beast is also forced out if the target regains its devoured brain by means of a wish. By spending 5 feet of its movement, the breaker beast can voluntarily leave the body, teleporting to the nearest unoccupied space within 5 feet of it. The body then dies, unless its brain is restored within 1 round.

Antennae. The breaker beast corrodes a nonmagical ferrous metal object it can see within 5 feet of it. If the object isn't being worn or carried, the touch destroys a 1-foot cube of it. If the object is being worn or carried by a creature, the creature can make a DC 11 Dexterity saving throw to avoid the breaker beast's touch.

If the object touched is either metal armor or a metal shield being worn or carried, it takes a permanent and cumulative −1 penalty to the AC it offers. Armor reduced to an AC of 10 or a shield that drops to a +0 bonus is destroyed. If the object touched is a held metal weapon, it rusts as described in the Rust Metal trait.