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AC 14 (natural armor), 10 while prone

HP 45 (6d10 + 12; bloodied 22)

Speed 30 ft., burrow 15 ft.

Proficiency +2; Maneuver DC 13

Damage Resistances acid

Senses tremorsense 30 ft., passive Perception 12



Claws. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 12 (2d8 + 3) slashing damage. If the target is a Medium or smaller creature, it is grappled (escape DC 13). Until this grapple ends, the target is restrained , and the ankheg can’t use its claws on anyone else. 

Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one creature grappled by the ankheg. Hit: 16 (3d8 + 3) slashing damage. If this damage kills the target, the ankheg severs its head.

Acid Spray (Recharge 6). The ankheg spits a 30-foot-long, 5-foot-wide stream of acid. Each creature in the area makes a DC 13 Dexterity saving throw , taking 14 (4d6) acid damage on a failure or half damage on a success. If the ankheg is grappling a target, it instead bathes the target in acid, dealing 14 (4d6) acid damage with no saving throw only to that target.


The ankheg lurks 10 feet underground, waiting for its tremorsense to register movement. It bursts out, firing its acid spray and then grabbing and biting the largest target available. It flees if badly hurt, dragging away any creature it has grappled.

Legends and Lore

With a History or Nature check, characters can learn the following:

DC 10 Ankhegs are giant insects that burst out of the ground and attack people and livestock.

DC 15 Ankhegs bite off people’s heads and spit acid. They have a hard exoskeleton but a vulnerable underbelly.

DC 20 Ankheg tunnels sometimes contain a huge ankheg queen and dozens of young, each bigger and fiercer than a mastiff.


An ankheg is a monstrous burrowing insect with ferocious mandibles. It is a scourge of settled lands, making a meal of sheep and shepherd alike.

Burrowers Beneath. Ankhegs prey on animals in the wild, but they observe no borders. Because they can burrow to safety, they’re hard to eradicate from settled lands. Ankheg tunnels can ruin farmlands and topple small buildings. Occasionally, their excavations turn up buried treasure or entrances to ancient dungeons.

Plague on the Land. In temperate lands, ankhegs often stay underground for years at a time, nurturing broods of young. After a cycle of 33 years, a region may erupt with hundreds of ravenous ankheg spawn that devour every animal for miles before burrowing underground for another 33 years of inactivity.


1–4 Bursts from the earth to attack

5 Half aboveground, eating prey

6 Dragging a struggling humanoid into its hole


1 Partially collapsed tunnels (possibly containing treasure from a previous victim)

2 Acid-scarred trees

3 The ground vibrating as if something is digging below

4 A big, half-buried, grasshopper-like shed skin


CR 0–2 ankheg ; 2 to 4 ankheg spawn

CR 3–4 2 ankhegs ; ankheg queen ; ankheg with 2 to 4 ankheg spawn ; 1d4 + 4 ankheg spawn

Treasure platinum armlet (250 gp), ancient brass key to an unknown door, 2 potions of healing

CR 5–10 ankheg queen with 2 or 3 ankhegs or 1d8 + 4 ankheg spawn ; 1d10 + 10 ankheg spawn

Treasure 900 sp, 450 gp, vial made of glass as hard as steel (250 gp)

Monster Type Description

Monstrosities are magical beings usually native to the Material Plane. Some monstrosities combine the features of beasts and humanoids, like centaurs . Others have bizarre or unnatural appearances, like many-tentacled ropers . Monstrosities could only arise in a world suffused with magic.