Wednesday, November 14, 2018

HD 1 Cosmic Monsters

When most people think about cosmic monsters, they probably go to Cthulhu and other Lovecraftian horrors.  Big, incomprehensible things that cause insanity when you look at them.

This is a pretty limiting definition, which is too bad.  It makes it tougher to use those themes at low levels.

not cosmic in any way, I just like this pic
Anyway, here's my attempt at some otherworldly monsters, who clearly aren't from around here.  My design guidelines:

1. Weird Biology

Not just "it has tentacles and a bunch of gibbering mouths".  Those things are weird because they differ sharply from normal terrestrial biology.  They are highly unnatural (perhaps even impossible) without being hard to conceptualize.  Impossible biology is the goal.

2. Weird Mechanics

Let the mechanics fit the theme.  I don't want them to attack and defend the same way that regular monsters do.  Their mechanics should reflect how unnatural they are.  Ideally, the players would have a moment where they say "oh fuck, I just realized how this thing fights".

3. Threatening

I'll admit that this one is debatable.  I mean, you could write a good story about a warlock summoning some fucked-up abomination that merely drags itself around for a few pages before dying messily, poisoned by our atmosphere or something.  But I want monster.

A really good follow-up post to this one would be Non-threatening Cosmic Monsters.  Or at least, monsters that don't kill you.  Can you write a monster that would horrify the players without threatening them?  (Of course you can.  That's why this is such a good prompt.)


On the wall of the dungeon, what appears to be a tiny tree grows sideways.  It has no leaves, and its limbs are translucent as the thinnest skin.  If it were standing on the ground, it would be about 3' tall.

All at once, the tree flies apart, and the separate branches come twisting through the air like stiffened bubbles.  They hunt like a flock of fallen leaves, close to the floor.  Some are wobbling forks, while others are linear, and coil through the air like arthritic worms.

HD 1 (HP 1)  AC leather  Bite 1d6
Move as butterfly  Int 6  Mor -

Breed - When a dendricule hits you, it creates a new dendricule with HP equal to the damage dealt.  This ability works on any creature with a fleshy body.

If no other prey is available, dendricules will eat each other, eventually producing a mass of 1 HP dendricules.  Then they will reform the "tree", and wait.  They can wait a very long time.


It looks like a flat piece of ash, the size of your hand.  Or perhaps a shred of black paper, something a magician could easily fold up and conceal between his fingers.

It flies through the trees like a hawk, and all at once it pivots along some invisible seam and heads towards the knights.

It corkscrews as it flies, spinning like a pennant in the wind.

HDAC chain  Attach -
Move as hummingbird  IntMor -

Eyeball Attacker -- Regular armor is useless against a noctule.  Instead, it attempts to burrow through the eye sockets.  Fitted goggles give +2 Defense.  Eyes clenched shut = +4 Defense.  Eyes clenched shut with both hands covering sockets = +6 Defense.

Papery -- Any fire damage instantly kills it.  If it would take any piercing/slashing damage, it instead splits into two smaller noctules, each one with half of the HP (round down).  If this would result in a noctule with 0 HP, it instead dies.

Burrow -- After attaching to its target's face, it burrows in through the eye socket and consumes the brain through the optic nerve.  This occurs automatically on the next turn, and in invariably fatal.  The person's life can be saved if a torch is applied directly to the noctule (and the eye) during that turn.

Once a noctule has killed a target, they remain in the back of the eye socket for several hours, digesting the cognitive properties of their prey.  During this time, they are iridescent, and fragmented memories can be seen on their skin.  A careful hand can carefully remove a dormant noctule from the back of an eye socket and store them in a jar.

They reproduce asexually, by making nests in porous materials, often in a corner.  These nests resemble inky stains.

When killed, all that is left of a noctule is a small amount of foul liquid.


  1. These are pretty neat, do you mind if I use them for a CoC scenario that I'm writing?

  2. There was that other monster that eats people and sends them to a demiplane where there is another, larger version of that monster, that can also eat you and send you to a demiplane etc. etc. etc.

    Flight is a connecting feature of those two monsters. What about something can only attack you if you are touching the ground?

    Grues only attack when you are in the dark.
    Shadows only attack when there is light to cast them.
    What other situations are reasonably binary? Wearing armour? Using a weapon?

    1. The monster Angus mentions was the dog demon in Better Than Any Man, in case anyone is curious.

    2. Another set of binary critters.

      Speaking. A thoughthound resembles a large fat toad with no eyes. If you speak in the presence of a thoughthound, it leaps up and snatches the sentence out of midair, stopping anyone from hearing it. The words are connected to the speaker's thoughts, and so the toad starts thrashing about like a dog with a rope, trying to yank some memories or ideas out of the speaker's head.

      Silence. Tinny Beasties. A predatory kind of noise that proliferates in silence. Fortunately, they aren't built to live in our world, and are destroyed if exposed to noise. A good clean showtune can get rid of all but the worst of the beasties.

  3. Youve struck a gold mine here. These are horrifying and fun at the same time.

    I think I had managed to do something similar on accident without realising what possibilities such creepies as this provide.

    2 monsters I made for numenera sent players running, even when they werent as hard as players made them out to be.

    One was razor hound -Disolves into panes of glass that can operate independently. basically a one dog wolf pack,single creature that attacks as a swarm.

    Second one was friendly, or atleast non hostile silvery sentient goo mass, looks like a mix of humanoid upper body mounted on triangular pyramid, chased party thru tunnels menacingly rotating and scraping walls with lower sides of pyramid. All it wanted was the bits players stole from it back.

  4. This ... honestly really reminds me of JoJo's Bizarre Adventure, in a certain way? Like, especially the weird mechanics part. Either way, I really love this, and I'm definitely going to be using some of this design philosophy.

  5. The noctules are reminiscent of Gene Wolfe's "notules"; hyr the Book of the New Sun?

    Anyway. I love this idea! But I don't like either of these monsters much. Sorry. The problem with the dendricule, ISTM, is that it's a combat monster, and combat with it will be just too swingy. The PCs can kill it with one hit, and may well do so before it ever has a chance to do its thing. In that case, it's a non-threat. And if it hits and duplicates once, NBD. But if it gets lucky and gets several hits and duplications without itself being hit? Now you're looking at a possible TPK. I don't know your system well enough to run the numbers, but it seems like most encounters with this thing will either be trivially easy or Rocks Fall, Everybody Dies, depending on how the first few combat rolls go.

    Also, you mentioned that moment of "oh shit" when the players figure out how the monster works. That's great! But with this creature, if it gets a couple of doublings, there's no answer or response but to run away.

    The noctule has a similar problem: the outcomes aren't granular enough. Either you kill it before it hits you, or you lose an eye, or you die. That's old-school (1e rot grubs, 1e green slime) but not necessarily in a good way.

    I can sort of see both of these working as "monsters that will eat an NPC to show you that you're in a weird dangerous place". But I'd think twice before throwing either of these at my players.

    But, again, I love the concept and I hope you come back to this.

    Doug M.

    1. I agree, the dendricules are extremely swingy. In my defense, most fights tend to be swingy anyway, since advantages accumulate quickly once one side has lost a couple of members.

      I'm okay with swingy, though. I'm okay with some fights that the party blows through and some that become horrible routs. I think those end up making good stories. (How many greentexts have you seen about players being elated about killing their DM's uberboss in 1 round after a lucky series of crits?)

      In in Zangbad, one of the enemies is a white worm mass that "breeds explosively". Ignore a patch of them for a couple of rounds and you will quickly end up with a room that is filled with them, like a horrible swimming pool.

      You are absolutely correct that the noctule is similar to rot grubs or green slime. Those trap-monsters have their place, I think. There's even the precedent of bottling them for use against your enemies.

      Also, monsters with steep learning curves (like these ones) work best when players are allowed to learn them before they get over their head. If I used them, I would put a room with a single noctule early in the dungeon, and a room with three of them later in the dungeon. After an encounter with 2 dendricules, they party would find a room deep in the dungeon with a dozen.

      Lastly, I *did* think about making the noctule do normal damage. I chose to make it more like the rot grub because I thought that would be more interesting, not necessarily useful.

      I'm not designing an unchangeable video game. I'm writing a blog post meant to inspire new monsters. It behooves me to post weirder stuff, even if it isn't instantly usable. Some people will like the rot grub-style noctule and other people will adapt it where it merely does HP damage, and disappears into an eye-socket on a kill.

      That's my secret strategy: Write weird shit on the blog, so people can dial it back at the table. (The inverse is much less useful.)

    2. The rot grub seems to have originally been a punishment monster rather than a trap.

      "The bodies have been dead for at least a week. They're rotting and they --"

      "I search the bodies and take any armor and weapons to sell."

      "They're... they're really rotten and gross and disgusting. Some of them are, uhh, bloated, and they --"

      "I search the bodies and take any weapons and armor to sell."

      "Yeah, man, just tell us how much we find."

      "Okay... fine. /Fine/. You search the bodies, then." [begins flipping through Monster Manual]

      Doug M.

    3. It could be a useful compromise to make it damage the Int score, rather than hit points. It's also pretty horrifying to have a flake of darkness attach to your face and start sucking your mind out through your eyes. Bonus: the first PC so attacked will probably wind up taking double damage for a round or two when his friends try to cut it off with a knife.

  6. Made my first patreon pledge for this post - this is a niche that is always lacking in rpgs - just discovered your blog and it is really an awesome set of materials.