I've written about wandering monsters a few times in the past. Here are some of those posts:
Mixed Feelings on Wandering Monsters
Dragon Magazine: The Wandering Damage Table
Cumulative Wandering Monsters, or, Dogpiling
Wandering Monsters: Totals and Origin Points
But recently John "Beedo" Arendt has been running Dwimmermount as a pick-up game for his neighbors and/or their kids. He wrote about Wandering Monsters. As often happens with his posts, I'm inspired to write more.
Today I'll post about wandering monsters in general. Next post, probably tomorrow, will be the specifics of The Lost City and what I learned from the method I've used there.
One aspect of wandering monsters that I like is the way they make a dungeon active. It's both the illusion of an active, living space and the reality. Illusion in the sense that the dice tell you if something moves into your area, but nothing is actually moving around. The player-centric approach of gaming means you concentrate on them and just figure out if something comes to them or happens to be in an otherwise-empty area. It's reality in the sense that having wandering monsters means things really are changing during a trip.
In any case having the dungeon have some activity means you can't rest in utter safety and ease even in already-explored areas.
On a 12 or Less, A Monster Exists
I don't like "monsters from nowhere." A lot of the time I end up turning wandering monsters into just sounds heard or ones wandering by or distant sightings is the geography of place. If I roll up some phase serpents, they might well get to the PCs despite all the closed doors around the area. If I roll up a slime, it makes sense that it might have gathered in some corner of the orc-held area. But sometimes I'll roll giant beetles but doors block the way. Or a mana-dependent undead monster in a place bounded by No Mana Zones.
While I can explain these in some way, it's a strain that makes the wandering monster roll an exercise in GM quick-thinking. It also makes player precautions less useful (why close the doors, beetles and slimes get through any way) and makes the whole less believable. Players are less likely to see the subtle mystery in the giant lizard in the corridor between two secret doors you can only open with a magical passcode and more likely to think, "Geez, dungeons don't make sense."
I attempt to make most of my rolls "something nearby comes by" and less "some monster basically sprouts into existence thanks to the dice." This is why I like totals and origin points. Tell me how many are around, where they come from, where they are when they aren't around.
You don't need to be so meta or silly about it, but still, for me, this beats "pop in out of nowhere":
"Room 8: The Wandering Monster Ready Room
A kobold, a troglodyte, a troll, a giant, a lizardman, and a giant toad are sitting around the Wandering Monster Table [. . . ] An hourglass is sitting on a nearby table [. . . ] Then one points at the hourglass, and all the creatures cut cards to see who has to go out wandering."
- Ken Rolston, in RIP1 Orcbusters (for Paranoia).
It's Not Safe to Rest Here
John Arendt mentioned how wandering monsters mitigate against the 15-minute adventuring day. In my experience, they actually put an obstacle in the way of longer trips. To go on a longer dungeon trip you need time to rest and recover. This is especially true in systems like GURPS but also in ones with finite resources you recover with time (AD&D spells, Rolemaster spell points and spell adders, etc.). If you track food and torches and such, people will need to either tote more or go back to town for more. Wandering monsters will bleed resources, which calls for in-game speed (to avoid them) and yet drive in-game resources consumption (from time or HP or consumable losses in fights, or avoiding them) and push the in-game pace. The threat of them can mean the need to cut short a delve just to ensure you can survive the way out, which again pushes towards shorter delves.
That's without even knowing if the monsters appear out of nowhere or come from a finite pool. Without the dwellers of an area reacting to invaders, maximal resting and maximal use of power is essentially a good decision. With the dwellers reacting (or just showing up)
So, lots of wandering monsters: adds risk to expending resources, but also a resource expenditure. Can push players to get in, do the maximum killing-and-looting they can, and get out.
Fewer wandering monsters: makes expending resources less risky. Can push players to longer trips, because they more generally choose the encounters.
At least in my experience. Once I stopped rolling for multiple deadly encounters on the way home, making "run home" safer than "push forward," players were more willing to push the trips a little longer. I decided that, as the GM, I liked the threat of getting eaten by a grue on the way home but also to cut it short so more time was spent on the exploration and delving than on the dealing with lizards and cube-monsters and orc patrols on the way home. You can't bet you get home without trouble, but you can bet it's easier to go back than go forward. Which, perhaps counter-intuitively, drives you forward. Forward is reward and risk, back is just risk, and I want my game to be about pushing for the former and mitigating the latter.
If my players started to meta-game this too badly ("It's always safe on the way home, so let's expend everything!") I'd change back. But they're good about recognizing it's a compromise and realistically, their characters would hold back resources to ensure a safe trip. Plus, if they leave in good shape, I'm willing to handwave the trip back . . . but if they limp out trailing blood, dragging loot, and clearly low on resources, things will attempt to take advantage.
Short version? Perhaps one (or two rolls when Dogpiling) for horrid monsters on the way home. None if we're short on time and the PCs are in great shape.
You can see more on this tension in this post.
They Don't Need to be Monsters
My wandering monster tables include lots of non-lethal things.
- surprise obstacles ("the trail is flooded out!");
- unforseen trouble ("the rickety stairs collapses.");
- nuisance trouble (bugs, swamp miasmas, leeches, bothersome rats, etc.) resolved as Wandering Damage;
- noises and smells and sights
I find I like these more than the actual monsters. They're fast and efficient, they make the environment come into play, and their effects are felt in a purely negative way. It makes the lethal monsters more interesting. Giant ants feel more interesting after two or three times you've sat on fire ants or had army ants roll through your lunch break. The dungeon feels nastier when you keep rolling up dampness issues and fast-growing mold. The caves feel less empty when the PCs keep stumbling across blind little purple-ish worms and know it presages something much bigger.
Plus, at least in my game, it means every 9 or less I roll isn't a quick fight followed by casting Zombie and then resting. Which leads to more encounters, and more zombies. This way, some of the non-lethal rolls just suck away resources and deplete character abilities.
Lucky Us, It's a Friendly Beholder!
One thing I don't do enough of, though, is just roll a reaction roll for monsters. I should do this more often - just see, is this thing looking for trouble? Maybe it's friendly. Maybe it's unfriendly. Maybe it's normally a lethal and ornery monsters but today - geez, today has been awful, let's just pretend we didn't see each other. Maybe it's totally uninterested in them.
That's a flaw of my play style, and I think it's worth exploring. Make all of those reaction penalties players like to pile up worth something. "The beholder rolled a 13 reaction roll! Oh, wait, -2 for your Social Stigma, -1 for your body odor, -3 because it's Intolerant of Dwarves, -1 because you're all pointing weapons at it . . . , eh, 6 . . . it attacks."
"But what about our bard?"
"You made him invisible and stuck him four ranks back. Sorry."