Sunday, October 6, 2019


This post is for the GLOG Mech Challenge thundering around its small corner of the OSR Discord. Other pilots are: Lexi at A Blasted, Cratered Land, Ancalagon the Black at Of Slugs and Silver, Micah at Nuclear Haruspex, Princess in Yellow at Words for Yellow, rtx at Octarine Tinted, Vulnavia at The Lovely Dark, Skerples at Coins and Scrolls, and Gorinich at their blog.


Six pilots. One for each sense: sight, hearing, taste, smell, touch, and proprioception.

See the chairs: five in a circle, resplendent with tapered helmets and grooved handholds, round a column thickly veined with glimmering, twitching tubes, cycling eutectic fluids through shallow trenches surrounding each helmet. You must strip and put on a bodysuit before the chair will open for you, unfolding curvaceous metallic petals designed to cradle your reclining form while stifling the agony and spasms of neural feedback.

One chair, separate from the rest, open to the interior. No petals here, simply an unassuming morass of silvery restraints. You must be bound by helping hands if you wish to helm the ezcocotli.

Once the pilots are cushioned and bound, trigger the starting sequence, fingers dancing over armchair embedded haptic sensors and eyes flickering through tracking sequences designed to ease the brain into releasing its grip on individuality. The corpus will shudder under you, dim impulses racing though neurons and trailing their way down the corestem, calling out to the organs, rousing systems from their slumber.

The five columnar cradles will gently film over, but the sixth will gyrate to an erect position while the cranium fills with a cerulean fluid, and the propriocept will dissolve into the liquid. The solution, now a deep emerald, will drain from the cranium and begin cycling through the helmets of the Senses. Simultaneously, a threadlike needle thrusts into five brains, seeking engorged grey matter exclusive to k'ix.

At this point, all pilots (except the sixth) must Save versus a respective stat. Mutations do not impose disadvantage on this Save, but Insanities or powerful magic (curses, etc) do. Take each stat a Sense saved against and compile them. Those stats are now the operational stats of the Ezcocotli.

Sight - Intelligence
Hearing - Will
Taste - Strength
Smell - Constitution
Touch - Dexterity

All Saves passed: The ezcocotli achieves perfect sync. All abilities are available, and estimated operation time before irrevocable brain damage is 6d10 minutes.
4/5 Saves passed: The corpus is operational, but suffers from a sensory Drift. The abilities granted by perfect sync and the failed Sense are nonfunctional. Roll on the Drift table to determine what effects plague the deployment. Operational time 5d8 minutes.
3/5 Saves passed: The ezcocotli is functional, but suffers from a Drift, and the abilities granted by the failed Senses are unavailable. Operational time 4d6 minutes.
2/5 Saves passed: Warning lights flash as slivers of ice withdraw from your brain. The propriocept must Save versus Will to reincorporate. Reactivation can be attempted with a different arrangement of pilots once. If the second time fails, those pilots can never sync with that ezcocotli again.
1/5 Saves passed or less: The corpus quakes as uncoordinated signals spider throughout its system. All pilots must Save or die seizing, iridescent spittle flecking from their lips as torrents of foreign signals unwrinkle their brains. The propriocept is trapped in the system until another successful activation is completed.*

Sensory Drift (1d6)

  1. Synesthesia. When exposed to significant sensory input, another unrelated sense is triggered.
  2. Dyspraxia. Save vs Will each round or always go last in initiative order.
  3. Congenital analgesia. The ezcocotli cannot feel pain. It will still take damage, but that damage is unknown to the PC's. They'll figure it out when reduced to 0 HP.
  4. Photosensitive seizures. Save vs Con when exposed to scintillating/bright lights or collapse for 1d4 rounds.
  5. Input loss. The ezcocotli doesn't have access to the failed Senses and associated abilities.
  6. Alien hand syndrome. One arm performs its own actions. Roll reaction to see how it responds to any encounter. 

Ariel Perez

Base Rules for Ezcocotli Piloting:
Everything is scaled up by 6 from a regular humanoid perspective. Each round of combat is 6 rounds longer, damage from an ezcocotli to a smaller target is multiplied by 6, and any damage an ezcocotli takes from something smaller than itself is divided by 6. Each inventory slot filled with armor ignores 6 damage from small sources. Improvise details based on this guideline as necessary.

Since each normal combat round takes 10 seconds, a round of ezcocotli combat is a minute. Plan well when piloting. You won't have much time.

From the pilots perspectives, combat and spells function normally, and things that regular humanoids can't normally harm (like large buildings) now have HD of their own.

For every minute that the ezcocotli is active, it loses 1 hit point. At the beginning of every minute beyond normal operational time, all pilots gain 1 point of Will. This ability score damage is permanent.

Hit points are equal to the combined Stress maximums of each pilot minus any Stress the pilots may be carrying.

A quick reminder of how my Stress score works: it's (20 - [Will score]) / 2. A PC with 10 will has a Stress maximum of 5, while a PC with 12 Will has a Stress maximum of 4. If a pilot with a Stress maximum of 5 currently has 3 Stress, they only contribute 2 HP to the activated ezcocotli.

When HP is reduced to zero, a random pilot (never the propriocept) must Save versus their own Will. If they succeed, they desync and gain 1d4 stress. If they fail, they desync, and they gain Stress equal to the damage of the triggering attack (which may trigger additional saves). When a pilot desyncs, the ezcocotli loses access to that Sense and corresponding abilities, and suffers from a Sensory Drift if necessary.

If the number of synced Senses is reduced to 2 or less, the ezcocotli shuts down.* All synced pilots must Save versus their own Will, desyncing and gaining 1d4 Stress on a success, and gaining Stress equal to the last damage taken on a failure. The propriocept must then Save versus their Will to reincorporate, remaining in the system on a failure.

During a normal system shutdown (which takes 1 round out of combat with at least 1 HP), all the pilots disengage normally, except the propriocept, who must Save vs their Will. On a success, they reincorporate normally with 1d4 Stress. On a failure, they reincorporate with 1d4 mental inventory slots stolen from another player and 1d4 Stress.

Regardless of the shutdown circumstances, each pilot who participated in a deployment cannot pilot an ezcocotli again until they finish a long rest.

Most Sense abilites take a round to use.

If the propriocept has any class templates, the excocotli gains access to those features. Remember, all effects (except for time) are scaled up by 6: 6 times the range, 6 times the damage to humanoid size creatures, etc.

The corpus vary in size. Most are about 200 feet tall. All are bipedal. They move with the laboring tread of weary travelers.

Ezcocotli Types:

Pilot advice paragraph:
Some powers only work with sunlight or starlight. Pilots cannot use the same power twice in a row.
Sense powers exist as options for pilots, not the only things ezcocotli can do. The propriocept has access to all their class templates and abilities. Corpus deal 6x damage to humanoids and humanoids deal 1/6 damage to the corpus, but ezcocotli deal normal damage to each other.

Shambling, slope-shouldered giant with luminous yellow eyes and huge plates of greenish, rusted metal draped over its body. As it walks, black dust flakes from its joints. It carries a large stone net speckled with barnacles and dried seaweed over one shoulder.

Stat Alterations:
-2 to Str and Con, +2 to Dex

Sense Abilities:
Sight - Can see through large bodies of liquid, even in total darkness, and can melt into mist and emerge from any water sources that it can see big enough for it to crawl out of.
Hearing - The Tlaloque can produce a thunderclap loud enough to extinguish fires and crinkle concrete by snapping its fingers. (d6 damage)
Taste - Can drink an unlimited amount of liquid and regurgitate it as a high pressure stream full of muck and fish.
Smell - Can filter all creatures out of all water within sight by dragging its net through the water.
Touch - Lightning blasts out of the sky, coils its way down the Tlaloque's arm, and leaps at what the ezcocotli is pointing at. (d4 damage to Tlaloque, 2d6 to enemy ezcocotli)

Perfect Sync:
The net separates into a bunch of floating stone chunks that slowly orbit the Tlaloque. The chunks can be mentally directed to create long strands that can wrap around creatures (even noncorporeal ones), grab things, whips, etc.

Its physical form is defined by a lack of substance, but the many grey, frost-encrusted bands wrapping around something hint at a bony, puckered form with unnatural joints. Its head is encased in a single flawless sphere of obsidian, and its claws are jagged voids in space.

Stat Alterations:
-2 to Will and Dex, +2 to Con.

Sense Abilities:
Sight - Wherever the Tzitzimitl focuses (treat as human sight arc), other creatures cannot see. Its range of vision is broken by solid objects, the horizon line, or magical light. Ezcocotli may Save vs Con with disadvantage to see normally each round. In addition, the Tzizimitl can see in all directions under the night sky.
Hearing - Any sound the Tzitzimitl makes or hears can be redirected to emerge from another location it can see.
Taste - Any shadow cast by the Tzitzimitl can become a void. It can reverse the polarity of the void if it chooses, causing any consumed objects to spill out. Things that do not die in the void become strange. Ezcocotli will fall in if they fail a Save vs Dex.
Smell - The Tzitzimitl can inhale and suck up all the nearby air. The atmosphere comes back in 1d4 rounds, but takes time to leak into enclosed spaces. Ezcocotli do not need air.
Touch - Under starlight, anything the Tzitzimitl touches with ill intent ceases to exist. Ezcocotli take normal damage. (d8 damage)

Perfect Sync:
At night, the Tzitzimitl can teleport to any area touched by starlight.

Centzon Totochtin
A portly, enormous shape wearing a tight, wrinkled yellow jumpsuit streaked with garish green and blue stripes. Occasionally, massive tufts of crusty hair erupt from rifts. It has a huge, green-stained clay vase tucked underneath one arm, and huge ears sticking out of a skeletal head encased in glass.

Stat Alterations:
-2 to Con and Str, +2 to Will.

Sense Abilities:
Sight - Whenever sunlight reflects off the skull, it bounces a rainbow of colors on the surrounding area. Creatures the colors wash over suffer associated emotions a la Green Lantern.
Hearing - The Totochtin begins shuffling, beating on its vase and tapping its massive feet. Save vs Will or dance with it for 1d4 rounds.
Taste - The Totochtin throws the contents of its vase on something. Any creature the milky fluid touches (including ezcocotli) must Save vs Str or hallucinate a field of flowers, upon which rabbit skins cavort, fuck, and drink dust from bottle stumps. Lasts for 1d4 rounds.
Smell - Any creature close enough to smell the Totochtin must Save vs Int (ezcocotli save with advantage) or begin to hear a nonstop voice chattering in their head, alternating between tinkling jokes, screaming in despair, and a deep chanting voice overlaid with a cacophony of heartbeats. This drowns out normal hearing. Gain 1 Stress for every minute spent listening to this drivel.
Touch - If the Totochtin caresses a dead creature, that thing turns into a gargantuan, drooling rabbit with bloodshot, human eyes. (4 HP on the ezcocotli scale, bites for 1d4 damage.)

Perfect Sync:
The Totochtin takes a huge swig from the vase (somehow) and sprays it in the air. Everyone within sight range (including ezcocotli) must Save vs Con or become blackout drunk for 1d4 rounds. This ability can only be used once per deployment. Roll on the below table to see what happened!

What's Happening? (1d6)

  1. Ezcocotli are doing a breakneck tap routine in sync which has shaken 1d4 surrounding buildings down.
  2. Totochtin sitting cross-legged on the ground, picking up corpses from a massive pile, kissing them, and placing them on the ground as they turn into rabbits. 2d6 huge rabbits are cavorting around its feet.
  3. Orgies! Orgies everywhere! 
  4. The Totochtin is lying on its back across a couple buildings, unconscious, with a huge gash across its chest revealing fungus-matted hair and a large crack in its glassy skull. Your ezcocotli has lost 2d6 HP. 
  6. You awakens to blackness. You have a very large vase on your head. Before you can take it off, something thwacks you hard. Save vs Str with disadvantage or fall over.

A bulbous iridescent blue creature with spindly legs and arms crisscrossed in blackened rubber. It is slathered with a clear gel, and wears a massive golden helmet from the nose up. Its mouth yawns with slack lips and multitudinous slender teeth.

Stat Alterations:
-2 to Int and Dex, +2 to Str and Con

Sense Abilities:
Sight - The Cueyatl can focus on an object. That object is slathered in incredibly slick, foul smelling grease which causes seizing death to any human sized creatures that touch it. (1d4 damage to ezcocotli)
Hearing - Creatures that hear the Cueyatl croak must Save vs Int or go into a murderous frenzy for 1d4 rounds.
Taste - The Cueyatl can lick something and leave behind corrosive, tarlike saliva that turns into expanding foam when exposed to water. (Saliva/foam 2d4 damage to ezcocotli)
Smell - The Cueyatl can regurgitate a huge pile of decomposing matter. It can eat this stuff to regain 1d4 HP/round eating.
Touch - When the Cueyatl touches an ezcocotli, the target must Save vs Str at the start of 1d4 rounds or be paralyzed for that round.

Perfect Sync:
If the Cueyatl takes a huge bite out of something and spends a round digesting, it gains a beneficial mutation based on the qualities what it ate. All gained mutations last until the end of the deployment.

This list is by no means exhaustive.

Sheng Lam

Design Notes:
All these mechs are based off of mythological creatures from Aztec mythology. The abilities are hopefully useful as tools - some ezcocotli have a different set of powers than others. I'm pretty confident that any party could find a good use for each ezcocotli.

I know the majority of mech systems feature details on armor plating, energy costs, hard points, and size categories. I have absolutely no interest in creating and balancing a system like that. In my mind, the emphasis of piloting an ezcocotli should be on the players. Skerples, of course, has already done this, but I like to think mine is a convergent evolution.

The energy source for these things is your PC's sanity. If you step into the mech with a horrible fixation on cornhusk dolls, you may enter a downward spiral and eventually end up gnawing your legs off in a dark corner, giggling about braids and bean eyes. These things require stable meat to function. The cancerous, partially ossified brain tissue of a wizard is just perfect for this.

There's no dramatic death and dismemberment table. I don't think I need one. It's not the ezcocotli that takes the damage, it's the PC's. Besides, any good combat will have these massive creatures wreaking absolute hell on whatever landscape they fight in. Be sure to narrate screaming, fleeing crowds, numb, freshly orphaned children, bloody paste among crushed concrete, and the like. In my games, the PC's usually end up protecting people through their actions, so a lot of these creatures have collateral damage abilities to create a tension between "incapacitate the hideous monster" and "rescue the trapped children from face-melting acid".

The reason I used a x6 scale is because I want to be able to create a sense of pressure. Deployments are short. Get the job done. Also, since my combat rounds are 10 seconds, I could create a scenario where PC's struggle to accomplish a task around two fighting ezcocotli or attempt to hinder one before it does something horrible while a friendly one boots up.

Additionally, very powerful spells (3 MD and up), artillery, and strategic building demolition will have an effect on these things. Not enough to kill it (unless that deployment really has shit HP), but enough to tempt ezcocotli into spending a turn annihilating something.

I do indeed know that there are 7 senses. (Balance, proprioception, touch, smell, sight, hearing, and taste.) I chose 6 because I wanted to include one pilot for every stat I have and create an additional way to customize each mech.

While you can't alter the abilities of your ezcocotli (or can you?), each party can create a different playstyle depending on the class abilities of the propriocept, how many Sense saves they pass to activate the corpus, and the PC - Sense pairs. I feel comfortable with this level of customization - each deployment will be very different. If your party doesn't have 6 PC's, snag a couple of NPC's. It won't change too much because the group runs the mech anyway.

To my current players: don't read any further. Here be spoilers!

Sheng Lam is awesome
Alright. Remember the asterisks from before? Go back and take a look at the sentences they mark.

Each asterisk details a case in which the ezcocotli has a 25% chance of waking up from its horrible temporal-spatial lobotomy, ripping off its entropic shackles, purging the cryptosemantic slave-patterns from its causality, and going completely fucking insane. All the terror of an angry god's rampage without any hope of salvation (unless another piloted ezcocotli is in the area hehehehehe.) If an ezcocotli gains its freedom with pilots inside, its consciousness will drive them insane or the cradles will flood their brains with a chemical designed to induce quick death. Either way, those PC's are gone.

If you're a dick like me, don't be upfront about this danger. Hint at it, but keep it a surprise. Don't tell my players.

Enjoy these blood vessels (ezcocotli translated), and go read the other mech rules!

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