d100 Sea Cave Finds

A d100 list of found objects, unexpected sights, and strange encounters for your players to come across while exploring caves carved by the ocean’s fury.

Shallow caves can hold mysterious depths.

The constant lashing of ocean waves slowly erodes shores and cliff faces. Normally this would simply shrink the coast, but when there is a weaker zone in the rock, the waves carve fissures. The fissures deepen and widen over time as the combined force of crashing waves, broken rock particles, and compressed air gouge irregular, shallow caverns in the stone. While many caves are found at sea level, some relict caves can be found far above the water-level, serving as markers of ancient coastlines.


Sea caves, while shallower than other cave types, hold just as many secrets for your party to explore. They might find themselves hunting a monster in their coastal lair, following a pirate map to hidden treasure, or even stumbling upon a tumultuous underground ocean. The chaotic force of the sea lingers in the very stones, and antediluvian creatures might remain among fossils, perhaps not as inactive as one would hope…

When using this list, feel free to choose any options you particularly like. You can also let fate decide and roll a d100. Every fifth option in the list is more consequential than the rest, so roll a d20 and multiply by 5 if you want to ensure a truly unique encounter for your party.

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1. A cluster of dark blue fish eggs.
2. A hermit crab wearing a rusted metal helmet.
3. A silver circlet that smells of salt. When worn, characters can speak Aquan, but cannot understand it.
4. A raised pool of water. It tastes of mint and keeps the breath fresh for 24 hours. It does smell delicious to some monsters…
5. [Encounter] A group of steam mephits are having a community meeting to decide the fate of all other mephits. They cannot abide intruders who don’t understand the natural primacy of steam.
6. A large, fossilized skeleton set into the ceiling.
7. A stalactite column sprouts a mouth and whispers “Beware” before becoming dormant again.
8. For a brief moment, the sound of the lapping waves stops. If the cave is relict, the sound of waves can be heard instead.
9. A small vial of orange liquid. It smells like clay.
10. An altar of bones and seaweed. If a character touches it, the water level begins to rise in the cave. It continues to rise until an offering is provided at the altar.
11. An old string instrument. It looks brand new, but it cannot be. Right?
12. A fissure in the wall that resembles a fanged maw. A crimson ruby glitters in its depths.
13. A sodden campsite. It looks recently made. A pile of clothing, enough for three people, is neatly folded nearby.
14. A pit hidden by water. It is not dangerously deep but leaves a character soaked from the waist up. Small characters might not be that lucky. The water has a strange smell.
15. An elderly woman has a tidy hut set up in the cave. She claims to be over a thousand years old. The crone has a number of coastal druid powers and potions. If treated poorly, she curses a character to reek of sour fish for a month before vanishing in a puff of salty mist.
16. An abandoned rowboat. A satchel onboard holds candlewax and a seal bearing an unknown symbol.
17. An eel with an arrow through its jaw and a collar reading “Sparkles” in Aquan. The eel is still alive. It is the pet eel of a powerful vestraadi.
18. A pale tree with blue-green leaves dripping brine.
19. Blue dragon scales are scattered about.
20. [Encounter] The specter of a pirate captain believes the party is after his hidden treasure. Unfortunately, he was a rather unsuccessful pirate in life and his treasure consists of a few gold pieces and a portrait of himself.
21. A limestone statuette about the size of a thumb. It is shaped like a badger.
22. A train of slugs moving in a perfect circle. At the center is the crumpled corpse of a scorpion.
23. A rope hangs from the ceiling. Creatures nearby have an unnaturally strong urge to pull on it. Nothing happens if they do.
24. Vines grown into the cave through a hole in the cave ceiling. They retract slowly through the hole if touched while making hissing sounds.
25. A smooth, crystalline orb floats five feet above the cave floor. Characters who look into it can see reflections of their past, not as they were, but as they could have been. The crystal transforms into water if touched.
26. Kelp and seaweed cover the ground. It clings to characters’ feet as they step in it, weighing them down. The kelp is sticky but can be washed off with alcohol.
27. The sound of a bell rings throughout the cave for a moment. It is painfully loud.
28. The remains of a spelunker. He has a pack filled with rations, torches, and a toy rabbit. (3 units of stock)
29. Eight crystals are set into the cave wall. They are set in the shape of a rare constellation. This constellation happens tomorrow.
30. [Encounter] A torchlight can be seen bobbing up ahead. It is really a will-o’-wisp floating just beyond a hidden pit filled with sharp and surprisingly solid stalagmites.
31. A swarm of gnats hovers over a small pool of water. They immediately land on any character who steps in the pool, completely covering them, but not biting. Their buzzing almost sound like whispered words.
32. A bag of glowing mushrooms. When splashed with salt, they generate darkness instead.
33. A tiny lizard with wings. It almost looks like a very, very stunted dragon.
34. Merfolk remains grasping a silver necklace shaped like a sundered tentacle in one bony hand.
35. [Encounter] Bones and tattered rags litter the floor. While the characters are distracted by them, the grick hiding on the ceiling attacks.
36. Bright purple, carnivorous mushrooms grow from the stone. Rat and lizard bones can be seen amidst the caps. The fungi are part of a massive, intelligent rhizome. It is vengeful and might retaliate with Shroomitis.
37. A thick vapor fills the cave. It smells of sweat.
38. A crack in the cave wall. If any character looks into it, they see an eye looking back. Breaking through the wall reveals an empty anterior cavern.
39. An ornate hourglass. The sands run out with a “click” just as the party notices it.
40. A large pillar of pure salt occupies the center of a cave. Any creature that touches it turns to salt. Pouring fresh water on the creature returns it to normal. A solid salt statue of a cave bear is licking the pillar.
41. A humanoid finger. It always points towards the nearest body of salt water.
42. A character’s nose begins running. Profusely. At a rate of half a gallon per minute. It stops after five minutes.
43. Three wooden posts stand in a triangle. Any character standing between them becomes invisible to any creatures standing outside of the triangle.
44. The sound of a muffled argument fills the cave. It is impossible to make out any words, but boy do they sound angry.
45. [Encounter] The party has unfortunately stumbled upon an ancient, sacred cavern. The society that used to worship here has bound water weirds to protect it (DM can determine how many).
46. The rancid corpse of a massive ocean creature blocks the way deeper into the cave. Clearing it will be a very messy business.
47. A pirate’s canteen, filled with aged rum. Its spices conjure images of tropical islands. Literally.
48. The party’s shadows disappear. They reappear after a minute, causing characters to feel an unnatural chill down their spine.
49. A pile of rotting fruits. A rat shaped pendant sits atop it. Its whiskers twitch once every minute.
50. An area of the cavern is covered in green-yellow lichen. Eating the lichen grants a character the benefits of a short rest, but leaves a moldy, unflattering taste on their tongue.
51. A shield bearing a symbol of two fish, circling.
52. A corpse staked to the cave wall by pitons in its arms and legs.
53. An adventurer’s bag. Inside are a couple of citrus fruits, an empty glass bottle, and a green ribbon.
54. A beat-up crate. Inside is a massive knot of living and rather angry snakes with their tails tied together.
55. [Encounter] A young bronze dragon appears as a seal, watching the party. If they appear just, or at least good, the dragon invites them to sit and discuss the ethics of peasant revolutions for as long as they can stand.
56. A sapphire set in the mouth of a snake skull.
57. Stalactites begin to grow unnaturally fast, closing the way ahead in a matter of seconds.
58. A monkey with gills. It is wary of the party and flees into the sea if threatened.
59. One of the party members hears their name whispered through the cave. They are unable to identify the source.
60. [Encounter] A cyclops! It is particularly slow-witted, even by cyclops’ standards. If the party is smart, they might not even have to fight it.
61. A silver coin with the emblem of a ship.
62. The corpse of a seal. It appears to have been gnawed on by a much larger animal.
63. A broken sword with a handprint burned into the pommel. The handprint has 7 fingers.
64. A cackle echoes through the cave but is cut off violently.
65. Tremors shake the cavern. The party has to watch out for falling debris, sudden pitfalls, and larger ocean swells until the quake subsides (DM decides duration).
66. A seagull nest. The mother protects its hatchlings.
67. A shattered glass bottle.
68. A green, glowing orb floats toward the party. Once it is within thirty feet, it explodes in a ball of light and vanishes. Any characters looking at it are blinded for the next minute.
69. Purple algae on the cave floor arranged in arrow shapes, showing the path deeper into the cave. Stepping on the algae makes it emit sound disturbingly close to a little girl giggling.
70. [Encounter] A much larger stalactite than others in the cave. It is a camouflaged roper, waiting to pick off the weakest looking party member.
71. What appears to be a gold ore vein in the cavern wall. It is really pyrite but mining it might unearth other riches.
72. An awakened bat addresses the party, proclaiming that it has been waiting for worthy opponents. It is still just a bat, though.
73. A clear glass vial. A navy-blue liquid bubbles inside. Drinking the liquid fills a character with dread.
74. A sodden journal. The ink has run on every page. The only words still legible read “I’ve found it! This will solve everything! After so long, I finally know where…”
75. [Encounter] The party finds a group of pirates about to execute an ugly woman wearing chains. She is really a sea hag who had been causing problems for the pirates. She turns on the party if freed by them.
76. A tree sprouting from the stone floor, struggling to survive.
77. One member of the party begins hallucinating for the next ten minutes. They see their own face in every rock formation, usually twisted in various forms of agony.
78. Small pebbles begin moving. They turn out to be a uniquely rock-like species of crab.
79. The skeleton of a shark. Strangely, this shark appears to have humanoid legs.
80. A cluster of odd, bright orange flowers grows along the walls. Eating a petal heals a character similar to a potion of healing. The character also exudes a strong, citrus smell for an hour. The effect cannot be repeated until a full hour has passed. There are 13 orange flowers. Picking all has dire consequences.
81. A dusty, weathered pirate captain’s hat. It comes with matching eye patch.
82. An altar bearing the image of an old, forgotten god. There are so many tentacles… just so many.
83. A member of the party experiences severe déjà-vu.
84. A corpse holding a bouquet of flowers. The flowers are fresh, but the corpse is not.
85. An old, red-bearded dwarf is cooking seafood at a campsite. He invites the party for a meal. He has a number of tales from his sea-faring days but has since retired.
86. An evil-looking ancient tome written in Aquan. It is a merfolk cookbook.
87. Bubbles float up from a crack in the floor. If any pop, they emit a terrified shriek.
88. The walls look slimy. They feel slimy too. They also taste slimy, just in case that needs to be known.
89. A rusty timepiece. It is stuck at 4:18.
90. [Encounter] The cave is home for a pair of hippogriffs and their newborn. The parents fight to the death if they feel their child is threatened.
91. A map of a cave system. It quickly becomes clear that it is not the map of this cave system.
92. A mountain goat that watches the party from afar. It blinks with two sets of eyelids.
93. The remnants of a mining expedition. Nothing of value remains other than some shoddy shovels and torn tents.
94. An empty barrel that smells faintly of chalk.
95. A portion of the cave wall is made up of pure, unblemished metal. When a character looks into it, they see themselves with a different eye color. Touching the mirror knocks a character unconscious for a half hour. When they wake, their eye color will have changed to match. Their counterpart in the mirror has their old eye color now.
96. A satchel filled with fresh bananas, fish bones, and maple leaves.
97. Hissing comes from a small hole in the wall. Inside is the skull of a moray.
98. A pair of gloves are stuck to the wall. It takes a large amount of effort to remove them.
99. A dented, silver goblet. In contrast to its humble looks, it can hold two gallons of liquid.
100. [Encounter] Now they have done it. The party has unfortunately made too much noise and awoken the mighty master of the coast slumbering in the cavern.


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