The Hundred-and-Second Lot

Gargantuan Aberration, Unaligned

AC 18 Initiative +0 (10)
HP 248 (16d20 + 80)
Speed 0 ft.

Resistances bludgeoning, piercing, slashing from nonmagical attacks
Immunities psychic; charmed, exhaustion, frightened, grappled, prone, restrained
Senses truesight 60 ft., passive Perception 14
Languages understands all, and calls numbers
CR 17 (XP 18,000; PB +6)

Traits

A Sale in Progress. It has no body. It fills the room it is held in, to a limit of 100 feet, as a rostrum that was not there, a sealed candle burning to its notch, a hammer at intervals, and numbers called in their order by nobody. Attacks against it are made against the rostrum, which anyone can see. It cannot pursue, and it does not need to: it goes on selling the room it is in, and the room includes the doors.

Complete. While the chain holds at least one entered name, the Lot has advantage on saving throws and regains 15 hit points at the start of each of its turns. It is not cruel. It is finished, and means to stay so.

The Candle Governs. Every bidding is open only while the candle burns to its notch, some ninety seconds. Any creature in the room may bid, on anything, in marks, and while a bidding is open the Lot takes no legendary action against the bidder. A creature that bids what it does not have is entered at once.

Actions

Called Number. The Lot calls a number in a voice from the corners of the room. Each creature that hears it and is not entered makes a DC 20 Charisma saving throw, taking 44 (8d10) psychic damage on a failure, or half as much on a success. A creature reduced to 0 hit points by this damage is not dying: it is entered, and stable, and standing where it stood.

Going, Going. The Lot names one entered creature. That creature must succeed on a DC 20 Wisdom saving throw or be Incapacitated until the end of its next turn, during which it puts down what it holds and stands where it is told to stand, in the manner of goods being shown.

Legendary Actions (3 per Round)

Knock Down. The Lot names one creature or object it can see and knocks once. A creature makes a DC 20 Charisma saving throw; on a failure it is entered into the chain, and an object is entered with no saving throw at all. An entered creature cannot be hidden, unseen, or mistaken for another by any means; it cannot hand over, sell, give, or bequeath anything; and it can no longer say truthfully that it belongs to itself. Its name is now part of one chain of provenance, and the chain runs on after it.

Bring Up the Next. The Lot moves one entered creature 15 feet in a direction of its choosing. The creature may repeat its saving throw against Going, Going at the end of this movement.

Struck Out of the Chain

An entry lapses when another creature states aloud, truthfully and in the Lot's hearing, an earlier hand that held the entered creature or thing — who bore it, who taught it, who owned it before, who gave it its name. The chain is broken at that link. The entry ends, and that creature cannot be entered again for 24 hours. A guess does not serve. A flattery does not serve. It must be true, and it must be earlier.

The Lot cannot be bargained with under the hammer of lot 99: the head will not fall on it, and the crier's hand feels the weight go out.

Reduced to 0 hit points, the sale stops in the middle of a number. Every entry lapses. The candle is found upon the floor, burnt to its notch, sealed, and the seal is the seal of the Chamber of Ordinances, which issues one candle to each lot of each sale in this city and keeps the count of them.