Bonecage Constrictor

Huge undead, neutral evil

Armor Class 16 (natural armor)
Hit Points 175 (14d12 + 84)
Speed 50 ft.

19 (+4) 16 (+3) 22 (+6) 6 (–2) 8 (–1) 5 (–3)

Saving Throws Str +8, Dex +7
Damage Vulnerabilities bludgeoning, thunder
Damage Immunities poison
Condition Immunities poisoned, prone
Senses darkvision 60 ft., tremorsense 30 ft., passive Perception 9
Languages understands Common and Darakhul but can’t speak
Challenge 9 (5,000 XP)
Proficiency Bonus +4


  • Necrotic Prison. Creatures restrained by the bonecage constrictor’s Encage automatically stabilize at 0 hp and take no further damage from Encage. If a creature takes damage from another source while restrained, it suffers a death saving throw failure, as normal, but immediately stabilizes if that isn’t its final death saving throw.


  • Multiattack. The bonecage constrictor makes two Bite attacks and one Encage attack.
  • Bite. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 13 (2d8 + 4) piercing damage plus 7 (2d6) necrotic damage.
  • Encage. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 11 (2d6 + 4) piercing damage. If the target is a Medium or smaller creature, it must succeed on a DC 16 Dexterity saving throw or be caged within the body of the bonecage constrictor. A caged creature is restrained, it has cover against attacks and other effects outside the constrictor, and it takes 10 (3d6) necrotic damage at the start of each of the constrictor’s turns. While caged, a creature can see outside the bone constrictor, but it can’t target those outside the constrictor with attacks or spells nor can it cast spells or use features that allow it to leave the constrictor’s body. In addition, creatures caged within the constrictor can’t make attack rolls against creatures outside the constrictor. The constrictor can have up to six Medium or smaller creatures restrained at a time. If the bonecage constrictor takes 20 damage or more on a single turn from any source, it must succeed on a DC 16 Constitution saving throw at the end of that turn or all caged creatures fall prone in a space within 10 feet of the constrictor. If any of the damage is thunder damage, the bone constrictor has disadvantage on the saving throw. If the constrictor dies, a caged creature is no longer restrained by it and can escape from the corpse by using 10 feet of movement, exiting prone.
  • Crush. Each creature caged by the bonecage constrictor must succeed on a DC 16 Strength saving throw or take 11 (2d6 + 4) bludgeoning damage.


Necrotech creations are massive undead creatures made by a group of necromancers. In nations ruled by undead, these creations often act as siege weapons or powerful modes of transportation. Here, we present the necrotech bonecage constrictor, reaver, and thunderer.

This enormous, skeletal snake is crafted from innumerable humanoid skeletons, ribcage after ribcage linked together. Some figures struggle within the body of this monstrous creature, clasping at the bony cage.

Necromantic Amalgams. Rather than an army of skeletons, a powerful necromancer can instead assemble the bones of dozens of humanoids into something far more terrifying. Because of their mismatched parts, no two constrictors are exactly the same; however, they all resemble enormous serpents or centipedes: long stretches of rib cage supported by grasping hands or feet. Often, the head is made of several skulls, with the glittering lights of reanimation sparkling from dozens of eye sockets.

Traveling Prisons. The necromantic energy that suffuses a bonecage constrictor drains the life from any creatures trapped within it, but doesn’t kill them.

Instead, it keeps the constrictor’s victims on the brink of death, where they can be transported while docide and unlikely to fight back. While some ghouls and evil high priests use these constructs to bring back fresh corpses, more inspired necromancers have used them to carry hostages onto battlefields, bring back live prisoners for questioning, or even to carry reinforcements.

Section 15: Copyright Notice

Tome of Beasts 3 © 2022 Open Design LLC; Authors: Eytan Bernstein, Celeste Conowitch, Benjamin L. Eastman, Robert Fairbanks, Scott Gable, Basheer Ghouse, Richard Green, Jeremy Hochhalter, Jeff Lee, Christopher Lockey, Sarah Madsen, Ben Mcfarland, Jonathan Miley, Kelly Pawlik, Sebastian Rombach, Chelsea Steverson, Brian Suskind, Mike Welham

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