Principia Discordia

Principia Discordia => Propaganda Depository => RPG Ghetto => Topic started by: The Good Reverend Roger on November 28, 2010, 03:33:56 am

Title: Monster Factory for Pathfinder.
Post by: The Good Reverend Roger on November 28, 2010, 03:33:56 am
I decided to take some time off from the interbutts, and start building a new homebrew campaign.  I figured it was time to throw some custom monsters at the group, because they've been getting spoiled.  If anyone likes the ideas I post, let me know and I'll email you the Word files (97 format, but I can resave them as 2007 if need be.).

So far, I have the Fabulous Undead Medusa Sisters:

One medusa with three levels of rogue (sniper variant) and the vampire template...Look at her, and make a will and a fort save, or be mind-grabbed and/or petrified - or look away, and get sneak attacked, and one medusa with four levels of fighter (weapon master variant) and the mummy template...Hack you with the sword and mummy rot your ass with the off-hand slam (and an armor class of THIRTY FIVE).  Both can poison their weapons as a move action.  CR12 and 13 repectively, for an EL14 encounter.

And, for earlier in the campaign, a mutant goblin:

One goblin with the advanced, giant, and fiendish templates, with an extra arm just for fun.  Good challenge for a first level party.  CR3, a little on the wuss side (more like a two and a half).

I also took the time to re-create the monster template in Word, and that's up for grabs, too, so you bastards can contribute.
Title: Re: Monster Factory for Pathfinder.
Post by: Telarus on November 28, 2010, 04:05:33 am
I don't play Patherfinder much, but those are Awesome.
Title: Re: Monster Factory for Pathfinder.
Post by: Don Coyote on November 28, 2010, 04:07:18 am
You truly are a fiendish GM. I shall make burnt offerings.
Title: Re: Monster Factory for Pathfinder.
Post by: The Good Reverend Roger on November 28, 2010, 04:07:34 am
I don't play Patherfinder much, but those are Awesome.

Just finished a giant advanced Gibbering Mouther with the ghost template.  This shit is sick.
Title: Re: Monster Factory for Pathfinder.
Post by: Phox on November 28, 2010, 04:15:08 am
 :eek:

Those are deliciously evil. I was told by a friend of mine about a mummy that has some sort of sticky mucus. I believe it is in some book or other. Either way, the concept of one of the party dragging around the corpse of a dead mummy for 1d4 hours made cream. And those medusa vampires are twice as creamy.
Title: Re: Monster Factory for Pathfinder.
Post by: Mesozoic Mister Nigel on November 28, 2010, 04:25:41 am
I don't understand a word you just said, but it sounds fun!
Title: Re: Monster Factory for Pathfinder.
Post by: The Good Reverend Roger on November 28, 2010, 04:52:08 am
Just finished a giant advanced Gibbering Mouther with the ghost template.  This shit is sick.

DOESN'T FUCKING WORK. :crankey:

Fucking abilities are all con-based.  So now I have a giant, advanced gibbering mouther looking for another template. 

Half fiend, maybe?
Title: Re: Monster Factory for Pathfinder.
Post by: The Good Reverend Roger on November 28, 2010, 04:52:21 am
I don't understand a word you just said, but it sounds fun!

We're geeks.   :)
Title: Re: Monster Factory for Pathfinder.
Post by: Mesozoic Mister Nigel on November 28, 2010, 04:53:02 am
We're geeks.   :)

Um, while you were doing that, I made food?

It sounds like maybe you need one of me around.
Title: Re: Monster Factory for Pathfinder.
Post by: The Good Reverend Roger on November 28, 2010, 04:56:25 am
Um, while you were doing that, I made food?

It sounds like maybe you need one of me around.

Yep.  Move your butt down here.

Incidentally, got the new place lined up, moving in on Wednesday.

Big Goddamn 4 bedroom joint, 3 full baths, the works.  I don't want to discuss the rent.   :x
Title: Re: Monster Factory for Pathfinder.
Post by: Don Coyote on November 28, 2010, 05:00:47 am
DOESN'T FUCKING WORK. :crankey:

Fucking abilities are all con-based.  So now I have a giant, advanced gibbering mouther looking for another template. 

Half fiend, maybe?

use wis or cha instead of con.
Title: Re: Monster Factory for Pathfinder.
Post by: The Good Reverend Roger on November 28, 2010, 05:04:40 am
use wis or cha instead of con.

Other problem:  Ghost engulfs you, what, you just walk out of it.

It just isn't a ghost creature.  It's DR goes, 11 points of natural armor lost for 2 points of deflection bonus, all it's hit points go away, etc.

Needs something else.
Title: Re: Monster Factory for Pathfinder.
Post by: Mesozoic Mister Nigel on November 28, 2010, 05:16:39 am
Yep.  Move your butt down here.

Incidentally, got the new place lined up, moving in on Wednesday.

Big Goddamn 4 bedroom joint, 3 full baths, the works.  I don't want to discuss the rent.   :x

Holy shit!

3 bathrooms

I barely have the one!
Title: Re: Monster Factory for Pathfinder.
Post by: Jasper on November 28, 2010, 05:58:23 am
This could be a horror documentary:  When Mooks Optimize!  :lulz:

I love the ideas.  Makes me wish I had a group here, a little.
Title: Re: Monster Factory for Pathfinder.
Post by: Don Coyote on November 28, 2010, 06:21:38 am
Other problem:  Ghost engulfs you, what, you just walk out of it.

It just isn't a ghost creature.  It's DR goes, 11 points of natural armor lost for 2 points of deflection bonus, all it's hit points go away, etc.

Needs something else.

I'm a bit hazy but......hand wave that this ghost can engulf.
Title: Re: Monster Factory for Pathfinder.
Post by: The Good Reverend Roger on November 28, 2010, 05:53:01 pm
This could be a horror documentary:  When Mooks Optimize!  :lulz:

I love the ideas.  Makes me wish I had a group here, a little.

I used to write an article with a friend for Hack Quarterly, When Good Players/DMs Go BAD in which he would demonstrate how to break character classes, and I would demonstrate how to break monsters.

So fund a group.  It isn't hard to do.
Title: Re: Monster Factory for Pathfinder.
Post by: The Good Reverend Roger on November 28, 2010, 06:02:10 pm
Holy shit!

3 bathrooms

I barely have the one!

Master bedroom suite is three rooms, including the "bathroom", that would put Nero to shame.

Title: Re: Monster Factory for Pathfinder.
Post by: Jasper on November 28, 2010, 07:31:01 pm
I used to write an article with a friend for Hack Quarterly, When Good Players/DMs Go BAD in which he would demonstrate how to break character classes, and I would demonstrate how to break monsters.

So fund a group.  It isn't hard to do.

The problem is, I don't really D&D.  My preferred method is something like FUDGE with a focus on realism.  Hard to find a group for that.  Most players attempt to kill me when I even mention it.
Title: Re: Monster Factory for Pathfinder.
Post by: The Good Reverend Roger on November 28, 2010, 07:36:03 pm
The problem is, I don't really D&D.  My preferred method is something like FUDGE with a focus on realism.  Hard to find a group for that.  Most players attempt to kill me when I even mention it.

They're right.  Book rules or GTFO.
Title: Re: Monster Factory for Pathfinder.
Post by: Jasper on November 28, 2010, 07:39:17 pm
We usually do GTFO.  It's funner to do RPGs on long walks in the late hours.
Title: Re: Monster Factory for Pathfinder.
Post by: The Good Reverend Roger on November 28, 2010, 07:42:26 pm
We usually do GTFO.  It's funner to do RPGs on long walks in the late hours.

Where do you put the grid map?  The books?  The piles and piles of reference notes?
Title: Re: Monster Factory for Pathfinder.
Post by: Jasper on November 28, 2010, 07:48:26 pm
We would just agree on percentage rolls to arbitrate everything, based on what was thought reasonable and likely.  One of us might bring a TI-84 and use some homebrew calcs for some things.  One example was using a compound interest formula to calculate hit probabilities based on distance and skill.
Title: Re: Monster Factory for Pathfinder.
Post by: The Good Reverend Roger on November 28, 2010, 07:52:44 pm
We would just agree on percentage rolls to arbitrate everything, based on what was thought reasonable and likely.  One of us might bring a TI-84 and use some homebrew calcs for some things.  One example was using a compound interest formula to calculate hit probabilities based on distance and skill.

:crankey:
Title: Re: Monster Factory for Pathfinder.
Post by: Jasper on November 28, 2010, 07:56:46 pm
(http://i518.photobucket.com/albums/u346/heinous_simian/1290755151052.jpg)
Title: Re: Monster Factory for Pathfinder.
Post by: Don Coyote on November 28, 2010, 07:57:56 pm
We would just agree on percentage rolls to arbitrate everything, based on what was thought reasonable and likely.  One of us might bring a TI-84 and use some homebrew calcs for some things.  One example was using a compound interest formula to calculate hit probabilities based on distance and skill.

So...how is this more realistic?
Title: Re: Monster Factory for Pathfinder.
Post by: Jasper on November 28, 2010, 08:03:06 pm
So...how is this more realistic?

It sets practical limits to skill and shows a smooth gradation in hit probability for a shot's difficulty.  I think the guy who did that stuff also had memorized the effective ranges of many common rifles, so it was a fairly representative system.
Title: Re: Monster Factory for Pathfinder.
Post by: The Good Reverend Roger on November 28, 2010, 08:05:21 pm
Back on topic, I'm almost done with the Trogdor Template.


It's the one that gives the creature involved a big beefy arm sticking out the back of their neck.
Title: Re: Monster Factory for Pathfinder.
Post by: President Television on November 28, 2010, 11:31:40 pm
Back on topic, I'm almost done with the Trogdor Template.


It's the one that gives the creature involved a big beefy arm sticking out the back of their neck.

Sounds fun.
Title: Re: Monster Factory for Pathfinder.
Post by: The Good Reverend Roger on December 03, 2010, 04:45:03 pm
Other problem:  Ghost engulfs you, what, you just walk out of it.

It just isn't a ghost creature.  It's DR goes, 11 points of natural armor lost for 2 points of deflection bonus, all it's hit points go away, etc.

Needs something else.

I'm a bit hazy but......hand wave that this ghost can engulf.

You don't know my players.
Title: Re: Monster Factory for Pathfinder.
Post by: The Good Reverend Roger on December 03, 2010, 04:51:55 pm
Simple Trogdor Template

+ 4 Str
Grow a beefy arm out the back of your neck (1 extra attack, +2 grapple).
Gain multi attack feat.

May only be applied to living creatures, but may not be applied to oozes or slimes.

+1 CR

Advanced Trogdor Template

Gain special abilities as follows:

Burninate The creature can breathe fire as a 5' line attack, to a range of 60'.  This deals 1d6 damage per hit die of the creature.  Victims save reflex DC (10+1/2 creature's hit dice + constitution bonus).  This may be used 1/day + a number of times equal to the creature's constitution bonus, to a minimum of one.

Consumate V's  The creature increases their natural armor bonus by a number equal to their constitution bonus.

This template may only be used if the creature has the base Trogdor Template.

+2 CR
Title: Re: Monster Factory for Pathfinder.
Post by: The Good Reverend Roger on December 07, 2010, 06:03:05 pm
The Guido Template!

+4 con, -2 int, -4 Cha  Guidos are hard to kill, but kind of dumb and annoying.

Guido creatures never attack if they are alone.  There will usually be at least 5 creatures in any group initially.

Special abilities:

Pomade (Ex)  Guidos gain a +10 to escape a grapple, as if affected by the Grease spell.

Popped Collar (Ex)  Guidos are immune to vorpal effects and strangulation.

Bling (ex)  Guidos wear an obnoxious amount of cheap gold.  Treat this as a +2 armor bonus that stacks with any other armor bonus the creature has.  This cannot be transferred to any other creature, but the bling is worth 1d6X10 GP - double value if melted down - (20 pounds weight), in addition to any other treasure the creature has.

Fist pump (Su)  A guido creature may inspire other courage in other guido creatures as a bard of the same level.

Duck Face (su) A guido creature may, as a swift action, pull a "duck face" that acts as a hideous laughter spell, with a caster level equal to the guido's hit dice.  Will save = 10 + 1/2 hit dice + the absolute value of the creature's Cha bonus (that is to say, treat both positive and negative modifiers as positive).  This can be done once a day, though guido creatures will continue trying to use it constantly.

+1 CR
Title: Re: Monster Factory for Pathfinder.
Post by: Phox on December 07, 2010, 06:12:33 pm
Roger, would you mind emailing me your word docs for these? I am going to send them to my friend who is currently less than pleased with her players.  :lulz:
Title: Re: Monster Factory for Pathfinder.
Post by: The Good Reverend Roger on December 07, 2010, 06:14:15 pm
Roger, would you mind emailing me your word docs for these? I am going to send them to my friend who is currently less than pleased with her players.  :lulz:

I can't really email shit until about the 17th, as I don't have cable in the new house yet, but sure.

Or just pull them down off of here.  The creatures I'll hand over as soon as I can.  The templates are identical to those shown here.
Title: Re: Monster Factory for Pathfinder.
Post by: Phox on December 07, 2010, 06:17:00 pm
That's cool. Whenever you get around to it. I will certainly grab the templates myself.  :)
Title: Re: Monster Factory for Pathfinder.
Post by: The Good Reverend Roger on December 07, 2010, 06:41:42 pm
Any Pathfinder/3.5 spags interested in some of Terry Pratchet's Discworld series' creatures?

I'm thinking the exploding swamp dragons for starters.
Title: Re: Monster Factory for Pathfinder.
Post by: Requia ☣ on December 07, 2010, 06:55:19 pm
Consider doing things with Dire Lions, (depending on party level).  They've been blamed fro many a TPK in Pathfinder.
We would just agree on percentage rolls to arbitrate everything, based on what was thought reasonable and likely.  One of us might bring a TI-84 and use some homebrew calcs for some things.  One example was using a compound interest formula to calculate hit probabilities based on distance and skill.

This is the nerdiest thing I have ever heard of.  I don't suppose you remember the formula?
Title: Re: Monster Factory for Pathfinder.
Post by: Sister Fracture on December 07, 2010, 07:05:28 pm
This thred makes me :lulz:

 
Title: Re: Monster Factory for Pathfinder.
Post by: Cain on December 07, 2010, 07:09:10 pm
Any Pathfinder/3.5 spags interested in some of Terry Pratchet's Discworld series' creatures?

I'm thinking the exploding swamp dragons for starters.

Absolutely.  I think a Discworld RPG based on 3.5 rules would be amazing...except you'd likely have to kill the wizard for your own safety.  At least no-one in the party will be an elf, though, neatly solving any Drizzt clone problems.
Title: Re: Monster Factory for Pathfinder.
Post by: The Good Reverend Roger on December 07, 2010, 07:10:51 pm
Any Pathfinder/3.5 spags interested in some of Terry Pratchet's Discworld series' creatures?

I'm thinking the exploding swamp dragons for starters.

Absolutely.  I think a Discworld RPG based on 3.5 rules would be amazing...except you'd likely have to kill the wizard for your own safety.  At least no-one in the party will be an elf, though, neatly solving any Drizzt clone problems.

I'm not willing to go whole hog on a setting, but I can do the creatures.

I haven't read all of his stuff, and I could use some prompting/reminders of what creatures to do.  I've read the first Rincewind novel and all of the Sam Vimes stuff.
Title: Re: Monster Factory for Pathfinder.
Post by: Cain on December 07, 2010, 07:41:32 pm
Things from the Dungeon Dimensions - They are born of nightmares, and make nightmares, and are just generally nightmarish in general. They are not large ugly furry things; those are just bogeymen, and are generally much prettier. They are not demons either, as they do not rely on belief to exist. And the pretty ones look like a cross between an ugly octopus and an angry bicycle.

They crave life in a stable reality, so they try to break through into more ordinary dimensions such as the Discworld (it says something when the Discworld has a much more stable reality than the Dungeon Dimensions have). Magic weakens the boundaries between worlds, so the Creatures of the Dungeon Dimensions gather where there is a large amount of magic, waiting to break through. They also sometimes manage to come into the mind of a wizard, and these Creatures have an affinity to the number that is four-plus-four, so wizards try not to say that number (see The Discworld Companion).

Trolls - made of stone, become less intelligent in the heat.  Ruled by a near-legendary diamond troll referred to as Mr Shine, who does not suffer from heat-intelligence loss.  Have diamond teeth.

Dwarves - short, beards for both sexes, miners, expert craftsmen, very serious.  "King" refers to a chief engineer, except in the case of the Low King in Uberwald.

Elves - transdimensional parasites who are experts in illusion.  Capricious and violent, they take pleasure in taunting their prey.  Iron has a negative impact on their powers.  Divided between a King and a Queen.  Often appear beautiful, but this is a consequence of their illusionary powers.

Banshees - Pale thin humanoids with leathery wings that look like a cape.  Exceptionally strong, fingers more like talons.  Civilized banshees wail at a death because it is expected of them.  A wild banshees wail means death however because it is going to kill you.  Possibly more common in Uberwald and Lipwig.

Vampires - undead, require blood to live.  Not necessarily violent, many suffer from a highly advanced form of OCD, which allows would be vampire hunters to defeat them by throwing a bunch of seeds at their feet.  This OCD usually manifests itself in something other than hunting humanoids in non-violent vampires. Usually strong, capable of flight, susceptible to garlic, holy water, holy symbols, attractive young women dressed in exceedingly skimpy nighties and developing long and esoteric sounding names to pass the time.  If reduced to dust, a drop of blood on the ashes can restore a vampire.  They are effectively immortal.

Ambiguous Puzuma - This leopard-sized big cat is the fastest animal on the Disc : it achieves near light-speed, given the low speed of light. This means that it cannot be proven to exist at any given time. Quantum anxiety, therefor, is a leading cause of mortality, along with ankle injuries from chasing females who aren't there.  While it can never be seen, due to its extreme velocity, remains are found, occasionally, on the sides of cliffs and large rocks. These show a black-and-white checked coat and a thin, flat shape.

Basilisk - A rare creature found in the deserts of Klatch. Twenty-feet long with acidic venom. Its famous stare is rumoured to turn people to stone; while this is not true it will do the same thing to the mind as a blender would do to a tomato.

.303 Bookworm - A small creature that has evolved in the highly magically charged environment of the Unseen University. Because magical books are often dangerous, the .303 bookworm has evolved to eat books at incredibly high speeds. It can often be found shooting out of books, ricocheting off the opposite wall. This presumes that unlike other maggots, it has an incredibly hard carapace, as a normal pupated lifeform at those speeds would just go "splat", which means it misses out on the next stage of its personal development (the chrysalis followed by the mature insect). In fact, going "splat" at the worm stage would mean the species dies out, as only the mature adult may breed the next generation of .303 bookworms... so there must be some sort of hard resilient carapace enabling the creature to survive the richochet. By extension, a direct hit on anyone standing in the way would be fatal?). This makes it the fastest animal on the Disc (saving only the Ambiguous Puzuma– unfortunately, a race would be hard to arrange and impossible to judge, due to quantum uncertainty.)

Drop Bear - The drop bear is a predatory distant family member of the Koala which drops from a tree onto its prey. As a result the species has developed well padded backsides to cope with the drop. It lives in XXXX, although many doubt they exist at all. Rincewind was pretty sure he was attacked by them in The Last Continent. The drop-bear, or at least one of them, learnt a fairly important evolutionary lesson: never drop bottom-first onto any target, however tempting, which is wearing a sturdy and rigid pointy hat on its head. Whether it is capable of having any descendants to pass this lesson on to is a different story.

Megapode - A strange, rare, and retiring mythological beast which apparently is only seen in Unseen University once every hundred years. It is apparently a man-high flightless bird and coloured scarlet and yellow. It is not, in the opinion of Smeems the Candle Knave, the Egregious Professor of Cruel and Unusual Geography in a silly costume.  Once seen, it must be hunted, with cries of "Ho, the Megapode!"

Quantum weather butterflies - These butterflies (Papilio tempestae) have wings of an undistinguished yellow with black mandelbrot patterns, and fractal edges of infinite length. A quantum weather butterfly can "create weather" merely by flapping its wings. It is possible that this is a sexual characteristic, that a male quantum weather butterfly will flap its wings and create, perhaps, a freak gale a few miles off, to show off its powers so to court a female quantum weather butterfly. Also, a quantum weather butterfly can make a small thunderstorm over, for example, the head of a bird that is trying to eat this butterfly, so the butterfly can flee the place and the bird might remember not to pursue such butterflies another time.

According to Vetinari in Feet of Clay, "the bodily fluids of the caterpillar of the Quantum Weather Butterfly will render a man quite, quite helpless."

Salamander - A lizard species that has evolved to live on magic. Salamanders look like lizards without a mouth. They live in deserts and sun themselves, absorbing all wavelengths in the Discworld sunlight. The salamanders use the octarine wavelength for their own energy and nutrients, and excrete the rest of the sunlight in much the same way that other animals excrete undigested matters. This excretion also happens when a salamander is surprised. Iconographers exploit this characteristic by keeping salamanders in a cage and using them as flashbulbs. In this capacity, salamanders have some roles in The Colour of Magic, Moving Pictures, The Truth, and most other occasions involving the use of iconography or the work of a newspaper.

Shadowing Lemma - A curious creature that exists in only two dimensions, and eats mathematicians.

Terrible Man-Eating Sloth of Clup - not much is known about this, except it is The Guardian of the giant ruby of the Mad Snake God.

Troll ducks - Nobody knows why evolution brought this species into being, as a silicon-based wildfowl is too heavy to either fly or swim. It is thought that they sink to the bottom and walk accross underground lakes.

However, the lake of pure mercury (re)-discovered by Rincewind in Interesting Times opens up a tantalising possibility. What if this is not an artificial construct, but a natural feature utilized by One Sun Mirror for his own ends?

If such liquid lakes exist naturally on the Disc, then an extremely dense medium which will neither poison a troll duck nor permit it to sink would be the natural breeding ground for the species...

Yeti - A sort of high-altitude troll adapted to living on very high mountains. Spins a thick fleece of extruded silicon fibres for warmth and bulk. First encountered in Moving Pictures when the distantly-heard Big Eats turn out to be a thousand indigestible elephants. On skis and sleds.

In Thief of Time we discover the species has an ability to manipulate time, so presumably the two specimens encountered in Moving Pictures learnt from what would otherwise have been a terminal encounter with a thousand elephants on bobsleighs - presumably they were able to pause and rewind, to a point where they could decide to be in a place where a thousand elephants on bobsleighs weren't. The Yeti's time manipulation is quite similar to the "save game" feature of video games on Earth. The Yeti is able to save its time at a certain point, and then venture forth knowing that if it dies, it can just resume its life from the point it saved at with the knowledge it acquired before death. It is effectively a highly evolved, albeit slightly painful form of foretelling. It is possible- as demonstrated by Lu-Tze- to learn how to do this without evolving it naturally, but given the difficulty involved in this method of survival when it isn't built in the person attempting it would have to be truly desperate to attempt such an action.

They are hunted for their feet, which as everyone knows have aphrodisiac qualities, as big feet mean other extremities are also oversized. Well-known fact, that is.
Title: Re: Monster Factory for Pathfinder.
Post by: Telarus on December 08, 2010, 09:27:53 am
:mittens:
Title: Re: Monster Factory for Pathfinder.
Post by: Cain on December 08, 2010, 02:33:13 pm
I was going to work on a list of races/classes for Discworld Pathfinder, but apparently the main manual has been deleted from my HD.  So it may take a little longer.
Title: Re: Monster Factory for Pathfinder.
Post by: Freeky on April 30, 2011, 05:33:01 pm
Shitfuckdamn, I thought the guido template was MINUS one, not plus one.
Title: Re: Monster Factory for Pathfinder.
Post by: The Good Reverend Roger on May 05, 2011, 03:08:34 am
So, the Resolute Lava Children, Caryatid Columns with whips instead of swords (for hauling people into lava), and the fiendish centipede swarm (for the bottom of the "Pachinko Trap") are done.

Only about 2 weeks more work to hand Hat his campaign-crusher.  Aiming for a TPK here, but doing so without violating game balance.  Any party that thinks things through and cooperates would do fine.  Needless to say, his yahoo players are doomed.  DOOMED!

muhaha
Title: Re: Monster Factory for Pathfinder.
Post by: Freeky on May 05, 2011, 03:54:32 am
:magick: 
Title: Re: Monster Factory for Pathfinder.
Post by: Jasper on May 05, 2011, 04:13:55 am
Consider doing things with Dire Lions, (depending on party level).  They've been blamed fro many a TPK in Pathfinder.
We would just agree on percentage rolls to arbitrate everything, based on what was thought reasonable and likely.  One of us might bring a TI-84 and use some homebrew calcs for some things.  One example was using a compound interest formula to calculate hit probabilities based on distance and skill.

This is the nerdiest thing I have ever heard of.  I don't suppose you remember the formula?

I just called him and asked.  

He said that he doesn't recall the exact digits he used, but his method was that you take the general compound interest formula, and set the current principal to a skill level up to 100 (for perfect skill.  80 would be something like mediocre to intermediate skill), and set the annual addition to zero and the interest rate to a negative number slightly less than or equal to -1%, such as -1.15%, to account for difficult conditions of the shot (such as fog, camouflage, movement, a bad gun, et cetera.  Again, sort out your own data for this since neither he nor I ever bothered doing the research to make a truly representative formula).  The years to grow is the distance from target variable, but you'd have to work out what units you wanted to use for yourself, since a shooter with perfect skill and perfect firing conditions only has a 66.9% chance to hit at 40 distance units, so make some kind of conversion formula to convert that to hexes or feet or metres or what have you.

ETA: The formula spits out a hit probability.

:)