Random Encounters: Indigo River Estuaries and Salt Marsh

When working through the Floundered Cog, I wanted to make the night and day and the high and low tides make a definitive difference in the gameplay - random encounters included. I like the way, in retrospect, that the ship, itself, is presented: but I am unsatisfied with the mechanical implementation of the wandering monsters for the "dungeon." Specifically, though it does isolate undead to the evening and it makes high tide (and evening) more lethal than low (or day), it does so without a cohesive presentation of probability. A Kelpie for example is a one-in-five change at low tide during the day; whereas at high tide during the night, it's one-in-thirty-six. More notably, Bullywugs - who are supposed to be our main antagonist, according to the fiction, against the intrusion of civilization - don't show up at all during the day in low tide: which seems like the best time to find a frog in reality.

So I wrote a random encounter table with a new mechanic to fit the salt marsh surrounding the Indigo River. Source materials include the monsters of Moldvay, the creatures of Cook, alongside the Fiend Folio and first edition Monster Manual.

Wandering Monsters - Salt Marsh / Estuary

Rolling Encounters

In the salt marsh, there is a 1-in-6 chance of an encounter roughly every four hours.
If an encounter is rolled, determine vaguely when during that period it will occur by rolling a d4.
To determine the type of encounter, roll two dice:

• During the night, the die rolled should be eight sided: a d8.
• During the day, the die rolled should be six sided: a d6.
• Depending on tide level, consult the correct column in the table.
• During periods of transition, the manner in which this process is modified is left to the discretion of the GM.

...and consult the provided table.

Encounter Table

Roll	High Tide	Low Tide
2	1-4 Kelpie (FF, 55)	1-3 Algoids (FF, 11)
3	1-2 Giant Catfish (X, 35)	1-4 Trolls (X, 41)
4	1-3 Bull Shark (X, 39)	2 Assassin Bug (FF 12)
5	1 Crocodile (X, 29)*	1-4 Giant Crayfish (MM, 15)
6	2-7 Salt Water Termites (X, 40)	1-4 Giant Toads (X, 40)
7	6-48 Bullywugs (FF, 16)	3-24 Buccaneers (X, 35)
8	1-8 Sea Snakes (B, 42)	Insect Swarm (B, 37)
9	2-8 Drowned Sailors (as Zombie: B, 44)	3-12 Former Settlers (Skeleton, B, 42)
10	2-12 Harpies (MM, 51)	1-10 Stirges (B, 43)
11	3-24 Sahuagin (MM, 84)	1 Giant Hornet
12	1-6 Wights (B, 44)	1 Shambling Mound (MM, 87)
13	2-12 Giant Crabs (MM, 15)	1-6 Shadows (B, 41)
14	1 Coffer Corpse (FF, 19)	1 Groaning Spirit (MM, 50)
15	1 Will-o-Wisp (MM, 101)	1-4 Apparition (FF, 12)
16	1 Ghost (MM, 43)	1-3 Spectre (X, 39)

     * Roll for size:

1-in-6: Giant

2-in-6: Large

3-in-6: Standard

Page References

B - Moldvay Basic X - Cook Expert

MM - AD&D Monster Manual FF - Fiend Folio

Why not use a preexisting table?

Although, truly, there is an abundance of wilderness and dungeon encounter tables themed around the marsh, I wanted the table for Watchtower on the Indigo River to reflect a few core principles:

1. Tide Matters. The tide changes the landscape and the things that live around it; so likewise should it change the adventure.
2. Circadian Rhythm. The sun and moon moving in slow sync across the firmament changes the atmosphere of the wild; so likewise should it change the tone of the adventure: motivating the players to take it into consideration during their planning.
3. Rareness of Rare Monsters. Some monsters, according to their source material, are more uncommon than others. I wanted the table to reflect that - producing small chances for uncommon creatures and large chances for common ones. Similarly, the creatures people talk about should be able to be placed as common - making reason to talk about them.
4. The Dead Walk at Night. Tied in to #2 above, undead are always scarier - and more abundant - at night.

Preexisting tables, though useful and many are more clever than this one, wouldn't be as easy to conform to those ideas as it would be to simply read through a few books and come up with something original.

Plus - making tables is fun.

Full Disclosure

Page references are done to the best of my ability; but I don't actually own a copy of the first edition monster manual. References provided therein are the product of an online resource I was guided to which, I have a hunch, has been tweaked or expanded by maintainers; hopefully it lines up with the physical copy - if not, I'll be happy to update this page accordingly.