Since I've been running fifth edition a fair amount, my version of the Temple of the Snail is likely to be there, located in the Heathwood of the Sorrowfell Plains. Since it gets referenced, here's a fifth edition-compatible version of the flailceratops from Vornheim:
Flailceratops Huge monstrosity, unaligned Armor Class 14 (natural armor) Hit Points 152 (16d12+48) Speed 30 ft. Str 22 (+6), Dex 9 (-1), Con 17 (+3), Int 2 (-4), Wis 11 (+0), Cha 5 (-3) Senses blindsight 60 ft., tremorsense 60 ft., passive Perception 10 Languages — Challenge 10 (5,900 XP) Trampling Charge. If the flailceratops moves at least 20 feet straight toward a creature and then hits it with a flail head attack on the same turn, that target must succeed on a DC 15 Strength saving throw or be knocked prone. If the target is prone, the flailceratops can make one stomp attack against it as a bonus action.
Actions Multiattack. The flailceratops either makes three flail head attacks against any targets of its choosing, or a stomp and a tail attack against different targets. Flail Head.Melee Weapon Attack: +9 to hit, reach 10 ft., one creature. Hit: 25 (3d12+6) bludgeoning damage. Stomp.Melee Weapon Attack: +9 to hit, reach 10 ft., one creature. Hit: 22 (3d10+6) bludgeoning damage. The target must make a DC 15 Strength saving throw or be knocked prone. Tail.Melee Weapon Attack: +9 to hit, reach 10 ft., one creature. Hit: 19 (3d8+6) bludgeoning damage.
This started as an exercise to figure out how to get players into a game for a session or two without having to jump through any narrative hoops to justify their existence. (Although I'm often fond of our usual "yeah, you're just there," that could get somewhat schizophrenic if new players are constantly cycling in and out.) It somehow turned into a weird cosmology thing, and a potential site for your adventurers to encounter. Or loot, if they're the standard gang of monsters and psychopaths.
Hidden from mortal eyes by the gods themselves (or so the legends say), the Valley of the Snail may exist locally to the realm in which it is found, although it seems equally likely that it travels the planes, slowly slouching from realm to realm on an arcane schedule. The valley is occasionally found by accident, by travelers in dire need, but is more commonly found by people who already know where it is located, whether by personal experience, anecdote, or ancient treasure map.
As pretty as the 5e art is, I still dig the Alan Hunter line work from the '81 Fiend Folio best.
When found, the valley is an idyllic forested valley which has no standard random encounters for the place in which it is found. Instead, it is host to several snails of various varieties. It also hosts 1d8+4 flail snails at any given time (they show up in the Fiend Folio and Volo's Guide to Monsters, among other sources). If left undisturbed, the flail snails will be docile. There is also a 10% chance that a flailceratops (from Vornheim, page 23) will be present.
If a flail snail is mortally wounded and begins wailing, there is a 10% chance every minute that an angry flailceratops will arrive. Likewise, a wailing flail snail will enrage all other creatures in the valley.
In the middle of the Valley of the Snail sits the Temple of the Snail. Made of a combination of wood and stone, it appears of vaguely recent manufacture, but that is only because its remaining Caretaker maintains it and replaces decaying pieces. The site of the shrine, and the intrinsic space of the temple, is millennia old. Many of the recycled stones are worn very smooth by the passage of centuries.
Whatever ancient race built this place (I went with elves, but you can pick whatever aeons-old, prehistoric weirdos you want) believed that the truest expression of divinity was the Great Cosmic Flailsnail that carries the planes upon its shell. As part of their ancient duty to defend the realms, they managed to harness the power of the flailsnail to summon heroes to their aid. The precise mechanism is unclear, although most scholars think it has something to do with the realms of Dream — they either summoned the echoes of famous heroes from their legends in Dream, or perhaps they snatched the heroes themselves from their own slumber as they lay dreaming in the Snail Quarter. Regardless, they were capable of summoning legends to their aid, to bolster their always-small numbers.
The Great Cosmic Flailsnail as illuminated by His Holiness, Sage Stneir. Probably pronounced like "Steiner."
Of that ancient kingdom, almost none remain; the Caretaker is the sole remaining member, and the sole inhabitant of the temple. (The current Caretaker in the Sorrowfell Plains is Lady Dul'besibrara Melithlylth'wyn, a Level 20 eladrin paladin with an Oath of the Ancients that allows her to maintain her unaging vigil. But again, determine whatever long-lived tie to an ancient epoch you want.) Although, as previously noted, allegedly "dead" civilizations intersect with the current age all the time, so you never know when you might meet another representative from outside of linear time. (So if you want to make things more complicated, maybe the PCs meet an ancient sage who claims the Caretaker is an impostor. But I digress.)
The Temple of the Flailsnail holds a massive flail snail shell in its tabernacle, potentially worth 50,000gp to the right buyer for anyone who can move the five-ton hulk. However, religious scholars and occultists might recognize the shell as practically beyond value, as it is but a pale reflection of the Great Cosmic Flailsnail, a dim echo of the vast beast's influence. Those trained in the old ways can chip away bits of the shell to make what are termed "snailstones," or "herostones" for those who lack poetry in their souls.
While the Sect of the Flailsnail could flawlessly extract and polish snailstones to assist their planar vigil, the current Caretaker can only produce cracked, flawed things. (Some scholars think the shell has a high talc and magnesium component due to similarities with magical soapstones, but then again, magic-users are always trying to categorize things they do not understand and are outside of their context.) A modern snailstone activates according to an erratic cosmic schedule, summoning heroes as the ancient Sect did. These heroes of legend are not confused about their current predicament, and are usually predisposed to be friendly to the wielder. (Although exceptions no doubt exist.) They disappear as mysteriously as they arrive. Assume they appear and disappear in an appropriately psychedelic flash of Kirbyesque colors.
If you don't have that Kirby Krackle in your games, what are you even doing?
In game terms, a player character holding a snailstone is perfect justification for a guest-starring player to bring their favorite weirdo into your game for a session without any context or lead-up, just arriving without fanfare and leaving when they have to go. I guess you could also use it to provide additional exposition and links to ancient conspiracies, giving guest stars pieces of information about distant epochs (assuming they are indeed legendary heroes from archaic days).
Six years ago, as a throwaway joke in my D&D campaign, the PCs discovered some hastily-written smut that purported to be the true tales of their adventures. As is often the case, that joke snowballed and turned into a publishing house, Quivering Whims Press. Their main offices are located in Tor Valuum, Anhak, but they have a major satellite office in Scandshar, as well as satellite offices throughout the Known World (and possibly across others, as well).
They're the local equivalent of a publisher of dime novels and pulp trash (and they publish an awful lot of erotica) — if any famous artists have come out of Quivering Whims, it's likely been by accident, the first half-dozen or so works by someone destined for bigger and better things. It's pretty clear that Quivering Whims is successful by volume more than quality of writing, although it's not entirely clear how they publish such large volumes in a world that barely has printing presses.
The mysteries of anachronistic fantasy worlds.
In addition to the aforementioned Tales of the Shields of the Sorrowfell, they have a few other popular offerings, including:
The adventure stories of Fap-hard and the Gay Mouser, of the fictional city of Yankmore, written by one “Slits Liber.”
The adventure stories of Elprick, written by one “Michael Morecock.”
Confessions of a Damned Lady, and the accompanying play, Strumpet of Blood, written by Orleck the Great (how they got a hold of a story from Cinder is beyond me).
I improvise a fair amount while GMing — I usually do whatever prep I'm going to do, and then react to whatever the PCs do with whatever tools I have available. (A random name list is essential, particularly since I appear to be consulting notes when referencing or generating names, so this NPC appears Important™.) It's why I dig the mid-part of a campaign: in the beginning, you have to establish lots of facts and generate content, but in the middle, you're just riffing off whatever has already been established. I'd be hard-pressed to say how much of what I run is improvisation, just because it doesn't feel like it; I'm just running off facts that have already been established, and bringing in new information as needed.
So I was pleased as punch about a month ago when I managed to run a session almost totally on the fly. (I used to run like that all the time, but it doesn't happen as often anymore.) I'm running Frostbitten & Mutilated, and in the previous session, my players accidentally unleashed a demon that rampaged across Rottingkroner. They subsequently decided that the road to Nornrik was a better place to be than in the city, so they fled. So all my prep involved generating some notable sites along the western road, and then letting random encounters do the rest. (Based on my map, the north road leads to the hexcrawl in the book, while the west and south roads lead to Nornrik. The south road curves around a mountain range, and so is longer but safer; the west road cuts directly through the mountains, but is less-traveled and more dangerous.)
They head west. They meet a new PC (playing the Doctor class from The Undercroft), bandage their wounds from fighting in the city (and so stop, only a couple of miles outside Rottingkroner), and are just in time to get slammed by an ice storm. They camp, and first thing in the morning, a frost giant rolls up. Three PCs — including the new doctor they just met! — die in the carnage, while the survivors and their hirelings flee back to Rottingkroner.
That's where the improvisation starts. One PC wants to start robbing houses to build up their finances for another expedition, and so sends the sneaky little pixie to investigate the wealthier houses in town. A roll on a random table yields a diorama of a recent battle the PCs had, which is clearly going to be the fight with the giant. I like that result because I also know it will entirely creep them out and inform whatever they do next.
While the pixie reports back and the new PCs show up (and I think there was pizza in there somewhere), I consult some more random tables, this time from Vornheim. (It sounds like they're gunning for patronage from this obviously weird, rich person, so I know I'll need them fleshed out.) A couple of rolls, a roll on a random name chart, and suddenly I have the owner. (And I happen to have an appropriate picture on hand, which I think really sold the whole thing.) Another roll for a random quest element mentions something about an ossuary holding demon bones, which sounds sufficiently like Elzemon and the Blood-Drinking Box from Chaos Rising to merit its inclusion.
I have all that done by the time they decide to show up at the house and confront this lady, and so they meet the beautiful and mysterious Bera Saemundsdottir, who is clearly using her husband's money to research occult subjects. (One of the PCs seemed to really hit it off with Bera.) She wants this dangerous box retrieved from a rival, and the PCs agree to it. (And now are trying to figure out how to rope in hirelings to feed blood to this damn box.)
As far as I can tell, none of the players noticed the changeover.
There's a Mike Mearls bit where he talks about the GM being the most engaged when the player characters change plans or mess with stuff, and that's absolutely true.
I was incredibly engaged the whole time, and now the PCs have a potential new contact and patron (provided they don't screw it up). Hopefully it works out as that patron will probably be important for some of the other stuff they've set in motion, but have not yet encountered...
(For that matter, November was a good month for improvisation and staying totally involved as a GM. As noted earlier in the month, D&D got so crazy that I was completely engaged for most of that session, and I even had to improvise a dungeon when a teleport went awry.)
Buried among the inequality of its typically-implied feudal setting, D&D has an implicit (and oft-ignored) transhumanist streak. High-level D&D magic breaks out of the utilitarian doldrums and goes fully post-singularity, creating the wretched cyberpunk dystopia of your nightmares. (And that ignores the possibility that your setting is literally post-singularity — all hypertech virtual GUI interfaces and half-mad shattered AIs as gods. Jeff Rients' World of Cinder operated under this paradigm, as does Anomalous Subsurface Environment, just to give a couple of examples.)
Perhaps more importantly, there exists the very real possibility that the world is haunted by the ghosts of its past realms.
The caveat that needs to be acknowledged: along with Star Trek, D&D isn't great at fully teasing out the inevitable consequences of its implied setting. (Two examples of Star Trek: they discover easy time travel that they rarely use and they introduce warp drive as causing an ecological disaster then completely abandon that subplot.) I'm not entirely certain it should be — we're just trying to run a game, not fully indulge in masturbatory world-building — but it's a fun little exercise to contemplate how a world would develop if someone can alter reality because they went to grad school, or because they have fire demons in their blood, or whatever.
So D&D is always figuratively about some mythic past as per Tolkien or Chaucer: "In th' olde dayes of the kyng arthour, / Of which that britons speken greet honour, / Al was this land fulfild of fayerye. / The elf-queene, with hir joly compaignye, / Daunced ful ofte in many a grene mede. / This was the olde opinion, as I rede; / I speke of manye hundred yeres ago. / But now kan no man se none elves mo." Adventurers interact with their environment in geologic time, encountering the earlier epochs of the realm's history as they delve deeper into the earth.
But there are a couple of significantly more visceral methods of interaction with the past, and they tend to be frequently neglected.
A Boot Stamping on a Human Face — Forever
It varies, of course, but most D&D settings assume some magic, even if it's past its heyday (again as per Chaucer and Tolkien). Unless you're in the lowest of low magic worlds, chances are good there's at least one vaguely approachable high-level wizard running around.
Although perhaps there are good reasons to avoid the wizards in your setting.
If said wizard is vaguely approachable, then it makes perfect sense that she would be making fat bank casting high-level spells (or scribing high-level scrolls, or manufacturing high-level artifacts) for people who can afford them. Once you get over the novelty of bossing people around with charm and dominate, or just manufacturing items on demand with fabricate like your own 3D printer, any aristocrat worth their salt is going to want to hang onto their wealth, preferably forever. So you get into high-octane, death-defying spells like magic jar (researched or imbued in a scroll so that others can use it, of course) and clone.
At this point, you now have a gentry with the ability to live forever, so long as they can keep pumping money into the system. It's Courtney Campbell'slich from his tricks supplement, representing "our fear of ancient rulers imposing their unending rule upon us," but describing mortal, magically-augmented people rather than the undead.
But it's basically the same effect: your ancestors bossing you around forever. Entropy never wipes the slate clean; the King must truly have divine authority if the King rules eternally. Altered Carbon and Tini Howard's sadly-unpublished Chamber Sounds both delve into this concept — the bastards who get there first gatekeep the rest of the schmoes trying to defy death.
And that's to say nothing of a potential hegemony of wizards capable of doing these things, although that concept is more frequently examined in D&D spaces (potentially including this very blog!) than the idea that the rich use their money to also benefit from said magic.
You can also get into a bunch of interesting permutations, like the magic-users capable of crafting soul jars or clones also forming a protection racket whereby they'll keep these important relics safe for a nominal fee. (And they'll blackmail you with the knowledge that you won't regenerate after your next death if you don't play ball.)
In Lordran, the Flow of Time Is Distorted
If you don't want to get too heavily into the transhumanist implications of potent D&D spells, then there's a more apparent aspect of D&D that probably merits examination.
Several spells are capable or returning the long-dead or otherwise preserved back to full life. There's a good example of some manner of greater restoration bringing a new player into the party (after prolonged existence as a statue) in this video:
Between restoring petrified characters, or using resurrection or true resurrection to restore the long-dead, it's entirely possible to have characters from historical epochs intersect with the present day. And that's without getting into bits of strangeness like long-lived elves, speak with dead, contact other plane, or whatever other magic one can find or devise.
Any historical fact-finding mission or archaeological dig can easily turn into a diplomatic mission when it turns out your primary sources can talk. Doubly weird because then they ostensibly integrate into society and inform that society — what happens when your ancestor whom you hit with a stone to flesh spell in the Temple of the Medusa tries to rejoin society a couple of generations after his contemporaries lived and died?
That's not, strictly speaking, a common occurrence, but it no doubt happens a non-zero number of times in any given fantasy society.
Now What?
Well, whatever you want, of course. If you want to take it to its logical conclusion, you have a cadre of elite wizards and super-rich nobles who can live and plot and scheme forever, viewing themselves as gods and the common folk as pawns. (Or maybe just a cabal of immortal and secretive sorcerer-kings moving behind the scenes. Or maybe a royal dynasty and their pet wizard. Whatever floats your boat.) There are a bunch of ways to play that scenario, with the caveat that the balance of power is likely to be the sort of precarious situation that player characters can inadvertently tip one way or the other — destroy a clone vat or cast a dispel magic in the right spot and suddenly everything is in chaos!
With regard to the other point, it's probably not a terribly common occurrence (unless you have a lot of basilisks in your world or perhaps just one mad resurrectionist), but it is notable that the past sometimes has a more direct voice in the present. Plus that lets you link in all manner of weird, ancient plots into your games — imagine a cult that leaves a handful of sleeper agents, bound in stone, and when some do-gooder adventuring party restores them to life, they can continue wherever they left off. That sort of thing.
If nothing else, it's an additional source of clues, characters, and plot hooks, to be sure.
