Sticky, overgrown mires polluted with noxious gasses and vile creatures- these depictions make swamps the perfect backdrop for villainous monstrosities. These tables are here to provide you with inspiration or random encounters to drop on your players and add some more life to the swamp environments in your worlds!
Sources
Each encounter focuses on a monster from throughout the D&D 5e library; to see what book or source they come from, you can consult the Book column. The sources unabbreviated sources are Basic Rules (BR), Monster Manual (MM), Mordenkainen Presents: Monsters of the Multiverse (MPMM), Icewind Dale: Rime of the Frostmaiden (RoF), Out of the Abyss (OoA), Volo’s Guide to Monsters (VGM), and Storm King’s Thunder (SKT).
Swamp Random Encounters
The following table provides random encounters for parties playing in various “tiers” of gameplay; they generally reflect encounters you can sculpt to work for tables within a level range. The Low-tier can work for levels 1-4, Mid-tier for levels 5-11, and the Upper-tier for levels 12+.
Low-Tier Adventuering Random Encounter Table
| d20 | Book | Encounter |
|---|---|---|
| 1 | BR | 1d4+3 diseased giant rats violently thrashing out at any travelers they sense |
| 2 | BR | A nest of 1d6+3 stirge hidden in the trees |
| 3 | BR | 1d4+2 bullywugs training a pair of giant frogs to eat other humanoids |
| 4 | BR | 1d4+3 giant poisonous snakes lurking in the underbrush |
| 5 | MM | 1d6+1 mud mephits mucking up paths commonly taken by merchants |
| 6 | BR | A swarm of rats nesting around a diseased giant rat resting in a rotting tree |
| 7 | MPMM | A band of 1d6+3 vegepygmys lurking to ambush their lizardfolk foes |
| 8 | BR | 2d4+1 black kobolds guarding the entrance pool to a young black dragon’s lair |
| 9 | MM | 1d4+2 black winged kobolds setting up traps to rain gunk on trespasser |
| 10 | BR | 1d4+3 crocodiles lurking below the surface for unsuspecting prey |
| 11 | MPMM | A scouting party of 1d6+2 darklings hunting a hag by the cover of night |
| 12 | BR | Four lizardfolk running a trading post |
| 13 | BR | 1d4+1 swarms of insects irritating travellers with endless bites |
| 14 | MPMM | 1d4 swarms of rot grubs infesting dead trees around an old path |
| 15 | BR | Three giant toads full from a dinner of overconfident hikers |
| 16 | MPMM | A black guard drake guarding a black dragonborn bandit captain |
| 17 | BR | Two druids with their giant toad companion search for rare herbs |
| 18 | BR | A giant constrictor snake feeding on horse that fled from its caravan |
| 19 | MPMM | A pair of meenlocks under the command of a green hag |
| 20 | BR | A green hag guarded by 1d6+2 bullywugs who made a bad deal with her |
Mid-Tier Adventuring Random Encounter Table
| d20 | Book | Encounter |
|---|---|---|
| 1 | MPMM | Two flail snails corralled by 1d6+2 lizardfolk |
| 2 | BR | 1d4+3 will-o’-wisps baiting travelelers into their ethereal glows for consumption |
| 3 | MPMM | A vegepygmpy chief and 3d4+2 vegepygmy warriors searching for a new home |
| 4 | MPMM | 1d4+2 redcaps thirsty for blood |
| 5 | MPMM | A pack of 1d6+2 shadow mastiffs hunting lifeforce |
| 6 | MPMM | Two catoblepas minding their own business, lounging in the swamp |
| 7 | BR | A giant crocodile wrangled by 1d6+3 bullywugs |
| 8 | BR | Two shambling mounds blending in with the underbrush |
| 9 | BR | Two water elementals composed of grime and flora caught in the swampwater |
| 10 | MPMM | A bodak and the 1d4+2 ghosts of the poor souls that entered its gaze |
| 11 | BR | A trio of trolls arguing over who gets the last lizardfolk leg for dinner |
| 12 | MPMM | Two venom trolls ruling over a bridge needed to cross the swamp effectively |
| 13 | BR | A young black dragon getting a mire-spa treatement from 1d6+4 black kobolds |
| 14 | MPMM | A corpse flower and 1d6+2 zombies meandering around its hunting grounds |
| 15 | BR | A hydra acting as the apex predator of the region, decimating wildlife near its lair |
| 16 | MPMM | A rot troll and two trolls who’ve claimed a flooded mine as their domain |
| 17 | MPMM | A froghemoth and 2d4+3 bullywugs worshipping it as a deity, feeding it captives |
| 18 | MPMM | 1d4+2 yuan-ti malisons seeking a yuan-ti temple lost to time |
| 19 | MPMM | An elder oblex and 1d4 oblexes tormenting a town bordering the swamp |
| 20 | VGM | A green hag nature coven determined to coat the world in their expanding bog |
Upper-Tier Adventuring Random Encounter Table
| d12 | Book | Encounter |
|---|---|---|
| 1 | MPMM | An archdruid and 1d4+3 giant crocodiles seeking a totem of a reptile god |
| 2 | MPMM | 1d4+3 spirit trolls defending their old lair’s treasure |
| 3 | BR | Two adult black dragon siblings sharing their domain and spoils |
| 4 | MPMM | A star spawn seer creating secret portal to herald in an ancient aberration |
| 5 | MPMM | A nabassu seeking a weak point in the plane to open an invasion from the abyss |
| 6 | MPMM | An ancient nagpa ruling over a society of 4d6 bullywugs and 3d8 lizardfolk |
| 7 | MPMM | A nightwalker awoken by hags, who it consumed before moving towards a city |
| 8 | BR | An ancient black dragon tithing the regions to near starvation |
