OSR: Hypothetical Time Periods

Time is another dimension.

Deep Time is weird. Recorded history is a blip at the end of a very long track. Tyrannosaurus lived closer to the Pyramids than to Stegosaurus. Geology and evolutionary biology work on a scale we can barely imagine.
Arthus Haas

Time Bandits

Jump into a time machine and end up who knows when.

Time portals are not stable. They only last for a few hours. They are rubbery - gasses and liquids can't move through easily. Solid objects need to be thrown or hit the portal at a good jogging pace. You and your fellow PCs are time bandits. You found a stable portal generator. Every few hours it opens in a new era of deep time. Sprint out, grab valuables, get back inside. Try not to get eaten by dinosaurs or giant amoebas or worse.

Each time raid is a sort of surface mini-dungeon. You can't explore more than a few miles from your portal. Maybe it's a gimmick in one part of a dungeon. Explore a few eras, then move on. Or maybe it's the basis of a whole campaign.

Based on the entries below, the GM should be able to visualize each period, describe it, and populate it with a few creatures, effects, or challenges.

Or stick each era in a room of a lich's time-traveling museum.

1d75+* Hypothetical Time Periods

*If you write your own list, link it in the comments and I'll add it to this table. 1d100? 1d200?

1-9: Coins and Scrolls
39. Plantagenetic Period
Basic principles of royalty discovered. Kings of bacteria, kings of slime, kings of trees, kings of fish and fowl. Metalosynthetic bacteria learn to produce gold crowns, form valuable layers of quick-dying rulers and usurpers. Iconography still visible under a microscope. Most hereditary lines trace their origin to this period. A catastrophic series of succession wars left only the lion (king of beasts) and some insect-based royal lines intact.

40. The Pseudopredatory Collapse
Mass extinction caused by the discovery that several apex predators were, in fact, cardboard cut-outs and plaster models. Arms race to claim the spots turns several innocuous species into vicious killers. Umber hulks evolve, smash the competition. Treaty of Mud, signed by most creatures (with eels and flatworms abstaining) bans vorpal claws, forces an unease peace. Parasite-spies steal evolutionary advantages and sell them to the highest bidder. Ends due to general exhaustion.

41. Desmodian Period / Retrodesmodian Period 
An asteroid impact causes the world to spin at a ludicrous rate. The sun rises and sets once a minute. Gravity effectively decreases. Creatures grow large, spindly, and aerodynamic. Rise of the mile-high giraffe and the faniform snakes. Several million years later, a second asteroid impact in the opposite direction returns the earth to its usual day-night cycle, leaving enormous twig-legged fossils scattered across the landscape. In mourning, everything becomes flat, slow, and boring for a few million years.

42. The CLF Non-Impact 
Radical bacteria, not content with caustic peroxides, begin synthesizing ever-more daring chemical deterrents. Azides, halides, and complex nitroaromatics, bubble inside high-pressure cell walls and teflon organelles. The only extinction event with a crater but no asteroid.

43. Orbiform Period
Animals roll across the landscape, slowly bludgeon their way into the earth, drift helplessly in the sea, bounce noisily through the air, and desperately try to remember how to evolve legs. Trees covered in thousands of balloon-leaves roll in vast forest stacks, like a migratory fruit display. Creatures unable to assume fully spherical shapes develop air pouches, thick fur, or shells. 

44. The Audit Boundary
Celestial auditors arrive to inspect early bacteria. Rapid growth and biochemical evolution creates extra paperwork. Auditors call for backup. Paperwork stored on land (currently unoccupied). Discovery of archaebacteria causes auditors to throw up hands in despair and depart, leaving three and a half continents covered in file cabinets. Paper-eating bacteria rapidly dominate biosphere, poison the atmosphere, and die. Coal from this period is very high quality, but contains staples and paper clips.

45. Miniature Ruin Period
Sentient swarms of mosquitoes evolve, develop sanguiculture, herd animals, writing, art, and swamp-based city-cisterns (like rice paddies, but fancy). Short-lived mosquitoes are fascinated by architecture, devote all their spare time to building elaborate miniature stone temples, cities, halls, aqueducts. Fossil layer is thick with microfrescoes and toothpick pillars. Arrival of the fire-breathing dragon-fly heralds extinction of their civilization, brief period of microdraconic rule and hoarding.

46. Worm Age
Denoted by a think sweet oil layer. One gigantic worm, immortal and ever-growing, takes several thousand years to reach full continent-covering size. Millions of creatures live in its folds. Eventually, food supplies are exhausted and the worm dies, collapsing the parasite food chain. Entire process starts again.

47. Remarkably Offensive Odour Period
Animals and plants race to become unpalatable by producing new smells. Chemosensitive creatures overwhelmed by custom-tailored disgust pheromones. Produces unbelievably smelly fossils, rich layers of sulphur. Giant anosmic millipedes become apex predators, drive most smelly creatures to extinction. The skunk is the only known survivor from the period (and proud of it).

48. Hostile Glaciation
Cold war between the ice lords of the north and the ice lords of the south turns violent. Murderous glaciers cruise towards the equator with freight-train speed. Stealth icebergs stalk the seas. Continents reshaped every few days. Nuclear winter without the nuclear bit. Lichen thrive as mediators, eventually broker peace agreement.

49. Saline Retreat
Comet eggs finally hatch. Newborn comets claw their way to orbit on pillars of ice and dust. Sea levels drop significantly, revealing land for the first time. Mass extinction of sea life as seas become saltier, shallower, and warmer. Land life consists of fur-bearing ice-tolerant lobsters, lice, and grey slime.

50. Taxonomic Fossil Boundary

Race of long-lived star travelers visits, deliberately and meticulously buries examples of life in silt-rich sediment beds. Giant lizards are euthanized, arranged, labelled, and carefully lowered into the mud by floating silver pyramids. Star travelers in diaphanous robes and fishbowl helmets wander the land, inspecting plants and checking lists.
Ramses Melendez
51. Escher Silicates
Conditions are perfect for minerals to accidentally form escher-paradox crystal structures. Rocks become very odd. Some are longer than they appear to be. Some are significantly heavier or lighter. Outer gods, eldritch entities, and time travelers arrive to quarry stone for non-euclidian construction projects. Entire strata buried by literal-minded volcanoes out of embarrassment.

52. Hypermagnetic Era
Core magnetism kicks into overdrive for a few million years. Iron aligns north-south. The ferrous pigeon, the rust monster, and the needle-nosed sky-shark evolve and thrive. Brilliant auroras allow for year-round plant growth and specialized ionized orchids. Magnetism gradually fades, leaving many creatures stranded without invisible means of support.

53. Glowing Boundary
A thin layer of radioactive metals, lead, and shocked quartz denotes an era of experimental radioactivity before cellular life evolved. Stone elementals build the first natural fission reactor. They are very proud of it. An earthquake during routine bi-millennial maintenance causes an explosive meltdown.

54. Accommodating Trees
Pressured by ravenous insects, smug lizards, and cunning rodents, a species of tree evolves to be extremely helpful. It analyzes creatures' needs in a brain-root and attempts to adjust itself to provide. Fossils show the trees producing knives, cages, hiding places, food buckets, rain sprinklers, and other bizarre growths. The accommodating trees rapidly spread across all major landmasses and are busy colonizing tidal swamps when a ravenous fungal infection wipes them out. Many species harbour genetic grudges against fungus.

55. Polychrome Coalbed Formation
Passing asteroid dumps billions of tonnes of plasticized paper flyers onto the planet. Inedible flyers smother most macroscopic life beneath waves of discount tentacle-cap offers. Slowly buried, fossilized, reduced to oily coal. Some advertisements still legible in the modern era (but inscrutable).

56. Hostagiferous Period
Giant ferns on a plateau slowly realize they can alter the world's weather system by increasing or deceasing local moisture and redirecting a vital warm air current. They demand tribute. Migratory birds deliver fresh nutrients, remove insects, clean and prune ferns. Ferns are carried to new lands on the backs of enslaved turtles. Eventually, continental drift removes fern control of the air current, though it takes a few million years for anyone to notice.

57. Third Bird Age
Oh for fuck's sake, get it together. Only lasts for a few years as everyone with access to a time machine travels to kick the period to death with hobnailed boots/clubs/ray guns. Paradoxical time bazaar punctuated by bird-hunting trips. Birds banned; everything else either permissible or mandatory. Fossils bizarre. Lots of beer cans.

58. Optical Period
A radical group of land shrimp develop transparent lens-claws. Focused sunlight burns and cooks their enemies. Surface creatures develop mirrored shells, thermal radiators. Land shrimp develop complex high-powered lenses, collaborative strategies, pack tactics, a taste for vandalism. Most forests burn. Unfortunate overcast era caused by high-altitude spider-cloud warfare drives lens-shrimp to extinction.

60. Fish Explosion
Fish population boom caused by runoff from land-based extinction event. Seas full of fish. Literally full. Water is either inside fish or in the gaps between fish. Small fish, big fish. Horrible stench. Interstellar herons fortuitously arrive and feast, leave giant platinum idols in thanksgiving.

61. Spongiform Tidal Interlude
Early bacteria learn to use gravity as a food source. Local gravity is extremely variable during the day, stable overnight. Combined efforts alter the moon's orbit, cause tides, swamp the surface rocks where the gravitosynthetic bacteria grew, wipe them out. A few species remain or are absorbed by other cells.

62. The Absence of Slugs
Documented in the fossil record only by their calcified retinas, giant slugs roam the land and sea, devouring everything, coughing up piles of bones. Slugs the size of buses, slugs with wings, slugs with soft crooning voices and mating displays, slugs with poison coats and venomous fangs. A primitive slug civilization with soft wood buildings and unfired clay tools. It's a vivid ecosystem, entirely unfossilized.

63. Bolionizoic
For reasons unknown, everything in this period became a pale grey-blue colour. Conifers, shrubs, grasses, hatchet-faced birds, flies; all the same shade grey-blue. Anything not grey-blue is rapidly surrounded by curious and possibly hostile creatures. 

64. The Second Rebellion
Primitive humans, newly self-aware, discover that sex results in children. Shockwave of despair half-collapses culture. Survivors, grim and determined, plan to invade heaven and demand answers. It doesn't go well. Marked in the fossil record by a thin sheet of sulphur, ash, and charred wood. 

65. Hyperadaptive Camouflage Period
Creatures learn to become invisible to light, then to sound, then to matter, then even to memory. Total absence. Cannot be recorded or imagined. Luckily, the prey creatures of the era (like clams with three legs) are relatively small, so the un-creatures were hopefully small as well. They are probably extinct. Maybe some of them survived and we don't know about it? Did they exist at all, or is this just a theory put forward to get a paper published in a high-end journal of theoretical paleontology?

66. Fulgurite Bugs
A species of beetle develops souls, religion, sin. Commits blasphemous acts to earn lightning strikes, vaporize predators, scatter cooked remains. No other redeeming features. Driven to extinction by crusading tree pigs lead by tree pig prophet.

67. Moral Period

Killer asteroid passes through upper atmosphere. Missed by a hair. Creatures take it as a warning, decide to become moral and upright citizens. Saber-toothed lions lie down with saber-toothed lambs. Plants produce delicious fruit just for kindness' sake. Self-imposed morality collapses within a few thousand years, leading to unparalleled vicious competition. Most animals vaguely nostalgic for this era.

68. Dontibundant Period
Teeth evolve from barnacles, seek warm mouths to colonize. Lizards, some fish infested. Some lizards evolve unwelcoming beaks. Trees, insects, and other unlikely hosts briefly tested, ultimately rejected. Thick beds of molars, primitive incisors, experimental corkscrews, hinged, flanged, or recursive teeth.

69. Era of Dire Hail
Massive equatorial storm systems whip up permanent hailstorms. Hailstones grow to the size of beach balls, develop miniature slime mold ecosystems, cultures, beliefs, leaders, ice buildings. Eventually they grow too large to float and either colonize adjacent hailstones or plummet to the ground. Oceans develop thin layer of floating ice. 

70. Pockmarked Zone
Wasp-like colony insect develops writing, learn to cast sigil-based spells, explosive runes. Sighted creatures flee in terror. Wasps driven to extinction by arrival of blind aphid hordes. Fossilized remains still explode the occasional paleontologist. 

71. Arthropodcalypse
Gigantic sea-scorpion-like arthropods emerge from the seabed, wreak havoc on land. Fledgling civilization of tuber-eating flatworm people devoured. Apocalyptic spiders rise up in joy, build triumphant banner nests. Giant arthropods die within a few hundred years, but by then the spiders have seized control. The world is locked in their eight-limbed grasp for several million years.

72. Repossessed Fossil Strata
Early mammals pledge bones to demons for help in war against birds. Victorious, the mammals grow large and ambitious. Megamammoths and skyscraper sloths prowl the landscape. Whales the size of island flap uncontested through the sea. After missing several payments, most large bones repossessed by demons, leaving a lot of useless boneless masses of fur and flesh to rot in the sun. Smaller mammals, scrupulous in their accounting, survive.

73. The Scouring of the Molten World
Star-faring strip-miners show up to collect iridium from slowly cooling world, just after its formation. Less precious metals (gold, platinum, mercury, molten sodium) tossed aside in fiery sprays. Atmosphere is mostly toxic, but there are mile-high heaps of gold just waiting to be taken (or tracked into the future for collection in a later era).

74. The Very Long Night
The sun is shut off for maintenance for a few million years. The world freezes solid on the surface. Occasional asteroid impacts and tidal heating keeps the deep oceans fluid. Surface bateria develop antifreeze, live by moonlight, go extinct when the moon is shut off a few million years later as the sun restarts.

75. Ironic Age
An exact repeat of an earlier era, but ironically. Creatures bring out disused proteins, activate archived DNA strands, dust off genetic memories. Some revert to single-celled forms (but, you know, ironically). Birds pretend to be dinosaurs, crabs dress up as trilobites, worms stay the same (but listen to old music), etc. 

76 - 77: The Amateur Dungeoneers

78 - 86: Swords and Scrolls
87 - 94: Profane Ape


  1. The three bird ages are the best. I also really like the idea of stupid, impossible history: How could everything be birds? Doesn't matter. It just was.

  2. I wrote more for shit and giggles: http://theamateurdungeoneers.blogspot.ca/2018/04/two-more-hypothetical-time-periods.html

  3. I've jumped on this bandwagon and offer the following (with more of a sci-fi bent): https://swordsandscrolls.blogspot.co.uk/2018/04/egradus-epochs-ages.html

  4. https://profaneape.wordpress.com/2018/04/29/deep-time/

  5. http://rememberdismove.blogspot.com/2018/05/more-periods-of-ancient-time.html

    A second one! Yay for d100+!