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Plains

Source Galaxy Exploration Manual pg. 76
Some plains nestle against venerable mountain ranges or gently slope to meet a glittering sea. Rivers meander across rolling lowlands or carve deep paths through otherwise flattened landscapes. Volcanoes spawn irregular fields of long-cooled lava, and distant, jagged mountains ring isolated plateaus.
It’s easy to think of plains as featureless expanses stretching to the horizon, but their steady elevations can host an immense range of flora, fauna, and terrain features. Floods or glaciers gift the lands they flatten with sediments that support an abundance of plant life, an alimentary oasis for beasts and sapient creatures alike. Temperature, latitude, and rainfall levels combine to create variations like tropical savannas, arid steppes, and frozen tundra. Jutting formations of deposited rock or inselbergs might dot a continent and be visible for miles around. Seasonal lakes and floods can reshape the land at regular intervals. Yes, plains are flat, but so is a painter’s canvas.
Adding alien elements to plains’ most familiar manifestations expands the canvas further. An immense starship crashes and skids for leagues, scraping some areas flat and ploughing up furrows in others to create disaster-birthed valleys. Gargantuan filter feeders might skim the landscape, the downdraft of their flight bladders applying enough force that only pressure-resistant life can survive. There could be translucent, shoulder-high grasses that crackle and sing with electricity as they ripple in frigid winds. An amoebic river might flood once per season—up into the air, where the planet’s strange atmosphere refines the liquid into nearly solid layers, with just enough room between them for rodents to forage for the river’s arthropods. Cracks in leathery ground ooze biological sludge, the substance nearly boiling beneath triple suns but cooling in winter into scabrous, nutrient-rich animal dens.
Life native to the plains adapts to the wide-open spaces and difficult-to-avoid weather. Trees likely have deep root systems to withstand strong winds, or form symbiotic bonds with creatures that can shelter inside them. Predators can take advantage of storms to hunt prey in their burrows or even charge their unique physiologies with lightning strikes or more alien atmospheric manifestations. The hunted might avoid hunters through high-speed locomotion such as flight or sprinting, or use early detection enabled by powerful sensory organs to give them time to conceal themselves. Others create cover that mimics rock formations or stands of grass.
The same conditions that create interesting evolutionary niches can cause trouble for adventurers, who must contend with bizarre storms and howling winds. The psychological elements can be just as difficult. Those unfamiliar with the plains and forced to spend long stretches of time there may become unnerved by isolation, the ever-receding horizon, or the ever-present wind. These same challenges likely make other features stand out all the more, be they solitary waystations or an unlikely social encounter. Other problems—and their causes— are of a larger scale, like ecological degradation from long-term resource extraction or smog settling over a heavily populated intermountain plateau.
Systemic problems usually mean sapient populations, and plains are natural population centers. Nomadic peoples follow herds of migratory beasts or windborne plants. Many such biomes are relatively easy to build on or cultivate for industrial agriculture; a busy plains city might sit at the center of concentric rings of multicolored farmland. These cities can also make natural transit hubs, as many are positioned between other metropolises, often because plains peoples were a key part of a planet’s early trade networks. Those networks usually facilitated cultural exchange, meaning plains societies can be important sources of historical or archaeological records. Others might wage war across expansive and familiar terrain, using speed to compensate for a lack of defensible positions. These same conditions could instead lead a society to value diplomacy to defuse threats before they can fully coalesce.

Plains Adventurers

Source Galaxy Exploration Manual pg. 76
Those hailing from plains regions are usually familiar with vast distances and long journeys. They might gain this knowledge in nomadic communities or by working long-haul shipping. Yearly on-foot sojourns across lush subtropical grasslands likely lead to aptitude for Athletics, while hours in the cockpit of a hoverhauler imparts knowledge of Piloting. Some are experienced at reading the sprawling horizon for weather signs. Others earn their livelihoods from the land itself through hunting prairie game or investigating a planet’s natural resources. Both categories make good use of the Survival skill. Resource seekers can be botanists, geologists, surveyors, and other professions that require Life Science and Physical Science skills. The Culture skill helps historians, diplomats, and archeologists; many arable plains make ideal population centers or facilitate transportation and cultural exchange. Given many plains’ lack of easily defensible positions—or the simple need to spot water, food, or shelter— plains adventurers are likely proficient in Perception. Lastly, many cultures have used plains for representing grand figures or establishing striking monuments; such devotees are almost certainly skilled in Mysticism.

Plains Worlds

Source Galaxy Exploration Manual pg. 77
Many plains worlds are likely created by the same forces that form typical plains, but on a global scale. A planet’s molten core may have vented long ago, covering the surface in smooth layers of lava rock, or an atmospheric anomaly might have evaporated a formerly oceanic world’s surface water. Perhaps melt or glaciation from polar ice caps takes the places of alluvial plains. Origins might be stranger still, such as a rhizome hive mind that shapes the world to its needs or an extraplanetary gravitational force that flattened great portions of a world.
Shared origin doesn’t have to mean a uniform surface. Uninterrupted wind currents are likely a large part of plains-world ecology, carrying seeds, soil, or even fauna across the globe. These might leave clear physical markers, such as windborne seeds that take root in colossal rivers of plant life that in turn attract migrating herds. The same winds likely interact with the planet’s axial tilt and temperature bands to produce diverse regions; it’s perfectly feasible for arid grasslands, tree-studded savannas, and tundras of bioluminescent lichens to exist on the same largely flat world. Lakes, rivers, and underwater aquifers likewise influence surrounding regions. For instance, subterranean water or a reservoir of homogeneous biomass would enable lush surface growth.

Plains Rules And Reference

Source Galaxy Exploration Manual pg. 77
River erosion can hide aquatic dangers or create chasms through long erosion, and alpine plains and plateaus might have high altitude conditions; rules for each of these environments can be found on pages 396–397 of the Core Rulebook. With wide open spaces and relatively few features, the storm and wind rules on pages 398–400 of the Core Rulebook can be important factors in a plains adventure. That same expansiveness makes the biome a natural fit for vehicle-based encounters and scenes. The Core Rulebook’s vehicle tactical rules begin on page 278, and vehicle chase rules begin on page 282. Long sight lines and a relative lack of obstacles provide the perfect sniper battleground; sniper weapons can be found on page 79 of this book, as well as in the Core Rulebook and Armory. The following Flip-Mats can be helpful aids for play in a variety of features found on plains: Starfinder Flip-Mat: Ice World, Pathfinder Flip-Mat Classics: Battlefield, Pathfinder Flip-Mat: Giant Lairs, and Pathfinder Flip-Mat Multi-Pack: Ambush Sites.

Plains Toolbox

Source Galaxy Exploration Manual pg. 78
See Biome Subsections on page 46 for advice on how to use the following tables.

Plains Inhabitants

D%	Sapient	Threat
1–4	Anacite	Apari
5–8	Angel, barachius	Assembly ooze
9–12	Cerebric fungus	Bloodbrother
13–16	Corpsefolk	Demon, pluprex
17–20	Dragon, blue	Dinosaur
21–24	Dragon, copper	Elemental, air
25–28	Embri	Flayer leech
29–32	Ghoran	Golem, nanotech
33–36	Giant, moon	Haeshi-shaa
37–40	Giant, stone	Hashukayak
41–44	Haeshi-shaa	Herd animal, plains
45–48	Izalguun	Hesper
49–52	Maraquoi	Jubsnuth
53–56	Nuar	Khefak
57–60	Osharu	Living apocalypse
61–64	Pahtra	Magmin
65–68	Quorlu	Moonflower
69–72	Ryphorian	Nyssholora
73–76	Scyphozoan	Predator, plains
77–80	Spathinae	Robot, assassin
81–84	Raxilite	Robot, siege
85–88	Trox	Scavenger slime
89–92	Verthani	Valnarum
93–96	Vlaka	Velstrac, anchorite
97–100	Witchwyrd	Void palm

Plains Adventure Hooks

D20	Adventure Hook
1	Local predators have evolved to cope with the thick grasses by developing highly attuned psychic senses that lead them to prey. A recently formed settlement of telepathic sapient creatures, unaware of the threat, has become a smorgasbord for the dangerous creatures.
2	An entire settlement’s populace is convinced that a rival settlement is involved in the recent and unexplained disappearance of dozens of domesticated herd animals while they were grazing on a nearby plain.
3	Unusual weather conditions combined with a quirk of life cycle have given rise to vast clouds of local insects. Trillions of hungry swarms sweep the plains, consuming all in their path—vehicle hulls and building materials included.
4	Every few years, the standing monoliths that dot the plains shift positions. No one quite knows why or how, but anyone who studies the problem too closely develops the affliction of the eyes that locals call “spire sickness.”
5	Capacitor trees gather static electricity in highly efficient organic batteries and then eventually explode, leveling the surrounding area and spreading their seeds far and wide. Recently, someone or something has been provoking these plants into exploding prematurely, causing widespread damage to the ecosystem.
6	Local tornadoes are combining with the razor-sharp amnion shards of local carrion-eaters to turn an already-dangerous weather phenomenon into a destructive force that can shred starship armor easily.
7	A recently discovered patch of leathery, waving grass was the site of a massive sinkhole that swallowed an entire vehicle— except this sinkhole has teeth, digestive juices, and internal parasites the size of dogs.
8	Void dragons have used these plains as ritual burial sites for eons, and mammoth skeletons dot the expanse. Dragon bones and funerary objects fetch a high price for anyone bold enough to offend the draconic hierophants.
9	Decades ago, unknown entities manipulated a chalk flat, cutting grass and scraping away the topsoil to form a desperate message. The incongruous emergency cypher is visible only from high altitude, and for that reason has only recently been discovered.
10	The sound of wind whistling through gnarled graytrees has long inspired local music. Recent research has shown that so-called graysong contains meaning-bearing patterns. Are the trees aware of their messages, or did someone engineer them?
11	A rare cyclical drought has revealed the outlines of an ancient city not detailed in any known records. Closer investigation reveals ruins deep beneath the earth.
12	The Aggregate Throne, an irregular rock formation that towers over the surrounding veldt, is the subject of numerous improbable local legends. The recent discovery of technological relics suspended in its inner layers shows some of these legends might be true.
13	Travelers to a mysterious section of a nearby windswept plain report that companions vanish in front of their eyes, even though there’s nothing but flat grassland in every direction.
14	Curious lights manifesting above a community resemble a distress call signature detectable many miles away. When nearby rescuers arrive, the town is abandoned, the soil blasted, and the plant life withered in odd patterns.
15	Nearby hydrocarbon fields provide an exceedingly lucrative resource, one that is harvested despite protests from locals and the sentient environment. Several opposing factions are planning decisive action and enlisting outside aid.
16	The farms and ranches of the region provide food for countless communities, but their production has ground to a halt after a recent campaign of sabotage. The perpetrator’s manifesto is about to become public.
17	The occasional trees that dot a local steppe share an immense root system. Their pollen has numerous medical uses but causes dangerous hallucinations in concentrated doses. A pollen-launch season, unprecedented in magnitude, is about to begin and a complacent populace is woefully unprepared.
18	Implausibly titanic sauropods amble slowly across the plains. Their physiology violates several laws of physics and mystical theory, attracting many researchers and trophy hunters.
19	A swath of verdant fields is unusually fecund and adapted to a sapient civilization: all the grasses bear large grains, the grazing creatures are well-fed and docile, and scattered plant life bears succulent fruits. However, there is no evidence of sapient life anywhere nearby.
20	Every cycle, the plains flood with several feet of water as rivers overflow their banks. Countless aquatic animals take the opportunity to wake from hibernation and breed, including an aggressive species of venom-spitting reptiles.

Archives of Nethys