Monster Of The Week: Ankheg

Tremors Rejects

Ankhegs in the fantasy universe are iconic.  Massive insectoid monsters with numerous slender limbs, burrowing through the earth and snatching unsuspecting prey from below.  Attacks are quick and often deadly to those without plot armor or an Initiative roll, so the only ones who live long enough to tell tale of these critters are those fit enough to fight them or those far enough away.  Keeping in mind their superior darkvision, blindsense, and their ability to sense vibrations hundreds of feet away...you're fighting arachnoid versions of the graboids.  
  The Ankheg has a long history in the realms of Dungeons & Dragons, but they haven't changed much.  It's hard to go wrong with "burrowing bug monster."  Why fix what isn't broken or problematic?
​  Let's take a look at the basics.

Ecology

Ankhegs are born by bursting out of the dead carcass of their father, eggs being implanted inside him by the mother during mating.  That's awesome.  From there, they grow to Broodling size and take nutrients delivered to them by their mother from the surface.  Within a year, they are big enough to leave the nest and burrow on their own, taking some time in their second year to shed their first shell and grow a second - during this time they're pretty killable, so they secrete a foul noxious smell.  Unfortunately, this can also make them easier to track.  Oops.
  A single Ankheg can rule a territory almost entirely unnoticed, snatching local wildlife and soaking up nutrients from the sun and ground as it hibernates.  Two or more Ankhegs will grow more aggressive over resources and will attack more frequently, drawing more attention to local towns and cities.  
  Their habitats can also cause problems to local infrastructure.  As little as 40 feet below the surface, with tunnels spanning upwards from 150 feet long, these winding burrows are known to rupture and cave in unsuspecting villages if left unchecked.  A single Ankheg's lair is one littered with bones and carcasses, with hollowed domes for hibernation or eating.   So imagine what that looks like with multiple bug-brains rooting around in the same territory.  They'll dig deeper and longer, and breed more; the cycle can devastate whole regions over a couple decades.  
  So, you know, always plenty of work for an Adventurer For Hire.

By The Numbers

Decent Armor Class (13-15) and one of the few creatures to actually offer a penalty to AC for being prone, these are still a strong challenge at low level.  Hit Points range from 39-66, so they can take some hits, and a Large size category makes them a tough sell for early Advantage.  What you have to watch out for is their 60 foot tremorsense and burrowing capability.  Their acid spray is no joke either, especially at low levels, and get these bucks in a pack and you might be in trouble (treat it like a breath weapon, and it recharges with a D6 roll).  It also grapples one creature at a time if it successfully bites them, and I've run and been at tables where grappled folks have received a face full of acid spray - it totally works.  Not nice to be up close for most folks.

Ankhegs At My Tables

After centuries of seasoned adventurers hunting them for their hide, acidic pouches, and resistant carapace, Ankheg broods have been burrowing deeper into the annals of Ionian geology.  Only the most chaotic of scholars have glimpsed their extensive underground networks.  The information they returned with spells a warning and a challenge to any that dare cross the Sandsea Of Jakt.  
  
BROODLING - descendants of the ancient wyrm, the Broodling is a tempestuous child, often found in birthing sacks (made from the dead husk of a mated male) hung from nooks in winding tunnels of an Ankheg Den.  Fresh to life, their carapace is still soft, resembling that of a young prawn.  Trappers believe that their hide actually more valuable in this state; as it is pliable and hardens over time, able to be shaped into effective armor.  It is this reason that drives trappers and young bounty hunters into the deep cords...and the reason that some do not make it back alive.  
  Broodlings hang in pods of 6-12 at a time, and must be harvested quickly.  For once that pod breaks, all of them wake up.  They're fast, frenetic, and feral.  Their pouches still growing, they instead use their pincer-like teeth to punch through armor in quick jabs, dealing 1d2+1 damage.  They also attack twice in their birthing frenzy, a note of caution to anyone thinking this is an easy kill.  Now, yes, their AC is 8, and Hit Points negligible, but all it takes is a few good strikes to fell the party wizard.  Still, if you can nab even a couple of these little guys, you should be sitting comfortable for a few months, especially after they shed that first armored coat, and that might just be the price of a level 1 wizard.
​SOLDIER - the Soldier Ankheg is the most common iteration of the creature, the textbook example in all its glory.  Smarter and stronger than a Broodling, the Soldier Ankheg hunts for itself or its Alpha, consuming, scarring, or capturing prey to be consumed later.
ALPHA - an Alpha Ankheg is a rare sight for most skirmishes.  Superior burrowers, the Alpha communicates to its Soldiers through an evolved vibration frequency, pushing and pulling them toward potential prey.  Though not every pack will have an Alpha, those that do operate with effective tactics - they lay traps, set ambushes, denote threats, and retreat if overwhelmed.  
  An Alpha in the field is a frightening visage.  Huge in scale, an Alpha is identified by its acidic scarring upon the external carapace in long swathes, resembling streaks of petrified bark.  These stripes are strongest part of the Alpha's armor, immune to acid and fire damage.  The Alpha's breath is also devastating; due to in-fighting within the pod, an Alpha develops an expanded bile sack, called the Leviathan Pouch, which coupled with their secondary throat produces an acid cone 60 feet long.  The Leviathan Pouch also allows extended use of the Alpha's breath, netting it three expulsions before it needs to recharge its bile (Recharge on a D8, 7-8).
  Their chitinous plating weathered and tempered, only seasoned warriors dare go toe-to-toe with an Alpha.  Resistant armors, healing potions, and blades lined with sharpening oil are their best bets.  A friendly cleric couldn't hurt, either.
​PRIME - Prime Ankhegs are myths.  Said to be Gargantuan in size, those that theorize of their existence point to the ascensions of new Alphas, where a Soldier Ankheg kills a wounded or aging Alpha, and takes their place.  The Soldier can only assert this dominance if they too have evolved their chitinous plating, a process of battle and time.  They surmise that if a pack of Soldiers without an Alpha lived long enough and fought hard enough, that each could evolve into this "ascended" state.  IF such a pack existed and vied for dominance within itself, could it not produce something even more powerful?  An Alpha among Alphas.
Beyond this thought, speculations abound.  A leviathan of the earth, consuming whole buildings in its wake, its brood a nightmare upon the material world.  Perhaps this creature exists beyond the imagination and machinations of the world's scholars, the seed of an ancient phantasm planted; or perhaps they exist already, a mutated corruption growing in realms beyond...

Happy rolling.
-Adamus