Chthonic Burrower

Lore & Background

Chthonic Burrower
Huge Monstrosity, Neutral Evil

Deep beneath the surface, in the endless caverns of the Underdark, the Chthonic Burrower reigns as an apex predator. Born from the fusion of elemental earth and primal hunger, these creatures carve labyrinthine tunnels through bedrock, destabilizing entire cave systems to isolate prey. Their bodies resemble living stone, veined with mineral deposits and glowing bioluminescent lichen that attract smaller creatures—only to be crushed under its massive claws.

Legends among deep gnomes and duergar speak of Burrowers as “earth’s wrath given form.” They are drawn to vibrations, sensing movement through miles of stone, and can collapse tunnels to trap adventurers. Some aberrant cults worship them as avatars of destruction, offering sacrifices to redirect their fury toward rival settlements.

Behavior & Role in Campaigns:

• Environmental Hazard: Collapses tunnels during combat, forcing players to adapt.

• Territorial Apex Predator: Hunts anything that disturbs its subterranean domain.

• Plot Hook: A mining operation awakens one, threatening to bring down an entire city.

Chthonic Burrower – Stat Block

Armor Class: 18 (Natural Armor)
Hit Points: 225 (18d12 + 108)
Speed: 40 ft, burrow 30 ft

STR 26 (+8) | DEX 10 (+0) | CON 22 (+6) | INT 6 (-2) | WIS 14 (+2) | CHA 8 (-1)

Saving Throws: Str +12, Con +10
Skills: Perception +6
Damage Resistances: Bludgeoning, Piercing, Slashing (nonmagical)
Damage Immunities: Poison
Condition Immunities: Poisoned
Senses: Tremorsense 120 ft, Darkvision 60 ft, Passive Perception 16
Languages: Terran, understands Undercommon
Challenge: CR 13 (10,000 XP)

Traits

• Tremor Sense: Detects movement through solid ground within 120 ft.

• Stone Camouflage: Advantage on Stealth checks made in rocky terrain.

• Tunnel Collapse (Recharge 5–6): As a bonus action, the Burrower can collapse a 20-ft section of tunnel, creating difficult terrain and forcing creatures in the area to make a DC 18 Dexterity save or take 21 (6d6) bludgeoning damage and be restrained under rubble.

Actions

• Multiattack: Makes two Slam attacks.

• Slam: Melee Weapon Attack: +12 to hit, reach 10 ft, one target.
  Hit: 24 (3d10 + 8) bludgeoning damage.

• Seismic Slam (Recharge 4–6): The Burrower slams the ground, creating a shockwave in a 30-ft radius. Each creature must succeed on a DC 18 Strength save or be knocked prone and take 27 (6d8) bludgeoning damage.

Legendary Actions (Optional for Boss Encounters)

• Burrow Shift: Move up to half burrow speed without provoking opportunity attacks.

• Stone Spikes: Cause jagged spikes to erupt in a 15-ft radius; creatures take 14 (4d6) piercing damage (Dex save DC 16 for half).

Adventure Hooks

• A duergar city hires adventurers to slay a Burrower before it collapses their stronghold.

• A cult worships the Burrower as an earth god, using it to sabotage rival factions.

• A dwarven mining expedition awakens one, triggering a race against time to escape collapsing tunnels.