PWYW Statosphere version with fancy formatting: https://www.drivethrurpg.com/en/product/415290/ua3-foetomancy

AKA Stinkers, Rotten Eggs

Everybody hates a bad smell. This disdain comes in part from an evolutionary desire not to die from e. coli, but it goes much deeper than that. We have countless olfactory euphemisms for evil, lies, and general badness, from a situation that “smells fishy” to “putting up one’s nose” at the unwashed lower class.
The thing is, foul odors permeate the natural world, from the bodily waste of all animals to the rafflesia arnoldii, or corpse lily. Three guesses what that smells like. Our own bodies produce a variety of stinks. Our response is an everlasting war on the very bad smells we ourselves create.
This is the root of the foetomancer’s paradox. While some might say the guy on the bus who hasn’t showered all month is “gross” and “standing way too close,” a foetomancer would appreciate the honesty of a man who refuses to hide behind layers of unnatural cleaning. Life is messy, and yes, sometimes it’s off-putting or unsafe. Foetomancers never shy away from that, whatever the cost to their social lives.

STATS

Generate a Minor Charge: Stinkers get a minor charge for every two hours they spend in a public place while smelling of something that will elicit a strong negative reaction from most people (such as fish guts or cat piss).

Generate a Significant Charge: The Foetomancer must make a frequently-used public space smell bad (by the same standards as a minor charge) for four hours. During this time, the space must be in active use. If the custodian is called in to clean up at the three-hour mark, the foetomancer had better stall or forfeit the charge.

Generate a Major Charge: Permanently imbue a centerpiece location of a community with a truly terrible smell, like burning hair. You can target a school, a government office, the only movie theater in a small town – that sort of thing.
But it’s not enough just to befoul the place. People have to continue regularly using it for at least the next year. If people stop coming to the park because the whole place stinks of melting rubber, even if they hold out for the first couple months, you don’t get the charge.

Taboo: A rotten egg mustn’t bathe. If they get caught in a downpour, they must seek shelter before they get wet enough to start washing their funk away.
Additionally, they cannot use any man-made products to make them or their clothing smell less strongly. This includes soap, deodorant, air fresheners, and washing machines. Yes, katharomancers loathe foetomancers.

Random Magick Domain: Foetomancy deals with bad smells and things that cause them, such as bodily waste, unclean substances, and decay. Its purview also includes being unrefined, uncivilized, and undesirable.

Ω: -1. Foetomancy’s taboo is just damning enough to decrease the school’s Ω. After just a week or two of adherence, people will begin avoiding the rotten egg, turning down their job applications, and that sort of thing. Ω is unchanged by the school’s charging methods, which are of standard difficulty.

Foetomancy Minor Formula Spells

CHEMICAL WARFARE
Cost: 1 minor charge.
Effect: This is the foetomancy minor blast. A single target within eyeshot takes damage equal to the sum of the casting roll dice as they suffer the effects if inhaling a poisonous gas. Their lungs, eyes, and throat burn and wither momentarily. This sudden onslaught prompts an Unnatural (5) check.

PUTREFACTION
Cost: 1 minor charge.
Effect: This spell ages and decays a small amount of nonliving organic matter. You can spoil a gallon of milk with it, liquefy cut vegetation, or even rot the flesh off the bones of a corpse. If you spend an extra 2 minor charges, you can affect a much bigger area, like a whole farmer’s market’s worth of produce.

HE WHO SMELT IT
Cost: 1 minor charge.
Effect: The foetomancer redirects the hostility, blame, or other negative disposition of a small group (no more than a dozen people) from themself to another person within that group. This lasts for a number of minutes equal to the sum of the casting roll dice. If the foetomancer leaves the scene, the antipathy immediately returns to them, however.
While it’s great for getting out of arguments and reducing revulsion, this spell doesn’t overwrite memories so if you’re trying to avoid the consequences of shooting someone’s dog or something, it won’t really help. And, of course, using this spell to help you get charges doesn’t work.

I CAN SMELL YOUR FEAR
Cost: 1 minor charge.
Effect: The stinker creates an atrocious odor evocative of an upsetting scene, localized in a space of roughly 3 square meters. It reeks so badly that it creates frightening images in the minds
of those who get a whiff. The hallucinations are tied to the smell; if you conjure au du entrails, people will imagine a scene of utter carnage to go with it. Because of this, anyone who willingly approaches or remains in the area must make a Violence (3-4) or Unnatural (3-4) check, depending on the smell
in question. The stench lingers for a number of minutes equal to the sum of the casting roll dice.
With the expenditure of a second minor charge, the stinker can instead invert the spell, creating a wonderful aroma. In this case, people feel an urge to approach, and face the Unnatural (3-4) check only if they don’t do so.

I SMELL A RAT
Cost: 1 minor charge.
Effect: To cast this spell, the foetomancer takes a deep breath through the nose. Anyone who harbors ill intent or a very strong distaste for the foetomancer smells like rat droppings, just for that inhalation. This allows the foetomancer to clearly identify these individuals.
The key word above is “very”. Most people don’t like foetomancers for obvious reasons, but this spell only indicates those who personally loathe the foetomancer, and those who are currently acting against them, or planning to do so.

MIASMA THEORY
Cost: 1 minor charge.
Effect: For a number of minutes equal to the tens place of the casting roll, the foetomancer can smell magick in the air.
If someone is an adept, avatar, agent of renunciation, or other unnaturally inclined individual, the foetomancer picks up on it. They can also detect unnatural phenomena and entities with this spell.

SNIFF THEM OUT
Cost: 2 minor charges.
Effect: The foetomancer gains the olfactory abilities of a trained bloodhound for a number of minutes equal to the casting roll. They can follow a specific scent, tell if the source of it is in a room with them, and they get a bonus of -20% to Pursuit rolls for tracking.

FOETOMANCY SIGNIFICANT FORMULA SPELLS

ALARM PHEROMONE
Cost: 2 significant charges.
Effect: The foetomancer applies a technique similar to that of a queen bee, emitting a magickal scent that invokes arousal in unnatural entities. Any unnatural entities that have a sense of smell and are in the same building or general area as the foetomancer are affected, all at once. This spell doesn’t exactly grant the foetomancer control over these entities. Rather, it allows them to evoke a sense of urgency in them, prompting them to follow a certain simple course of action, such as defending the foetomancer or leaving the area.
The entities find this course of action to be appealing and advisable. Many entities may still ignore the pheromone in favor of their obsession, lust for blood, or general contrarian attitude. This spell works best when the suggested action plays into the targets’ obsessions.

FIRE AND BRIMSTONE
Cost: 3 significant charges.
Effect: When a rotten egg casts this spell, they immediately start to reek of brimstone – that is, sulfur, which smells just like… Rotten eggs. This stench happens even if they fail the casting roll and will only go away if the rotten egg breaks taboo to bathe.
While under the effects of this spell, a rotten egg can expect to attract a demon every 1d10 days, likely at inopportune moments. The spell grants no control over these entities.
Unlike the smell it creates, this spell doesn’t last indefinitely. Every 3 days, there is a cumulative 10% chance that the magick wears off and the demons stop coming. If you get unlucky, you might not even get a single demon. If you get really unlucky, they could keep coming for weeks.

NECROSIS
Cost: 1 significant charge.
Effect: This spell is like Putrefaction, except it can affect living things. Use it to wilt plants up to the size of a topiary. On people and animals, it sadly doesn’t melt faces Raiders of the Lost Ark style. It withers and atrophies muscle, giving a target a +20% penalty on all rolls for strenuous physical activity. Being hit with this spell also calls for an Unnatural (5) check.
Each subsequent day a victim gets proper rest and nutrition, the penalty drops by 1d10% until it’s gone.

SILENT BUT DEADLY
Cost: 1 significant charge.
Effect: With the foetomancy significant blast, a victim’s insides shrivel with destructive force equivalent to a big lungful of mustard gas. They take damage equal to the casting roll and must make an Unnatural (5) check.

THE GREAT STINK
Cost: 1 significant charge.
Effect: To cast this spell, the foetomancer must be in physical contact with the person they’re targeting for at least 33 seconds. Once contact is broken, the person is placed under a sensory hex: everyone who knows them well enough to unconsciously recognize their scent (so, loved ones, coworkers, etc.) become repulsed by it. Anytime they handle the target’s clothes, sit in their car, or are face to face with
them, their heads fill with negative thoughts and unhappy memories related to the target.
Even if they want to fight this feeling, it’s there, gnawing at their mind. This will cause an Isolation (6-7) check for the target within a day or two, and Self checks of varying degrees for any of their associates who choose to stick around. The spell lasts for a number of weeks equal to the tens place of the casting roll, so by the time it’s over, bridges might already be burnt.

MAJOR CHARGE EFFECTS

Permanently attach any odor to a person or place. Reverse the general attitude of the public toward a specific smell. Fill a building with toxic gas. Create a soap shortage that lasts a year.