I know this post is a little late this week, but some personal matters halted me from devoting enough time to get it posted this morning. But now it’s Free Adventure Friday as usual and this week I have a dungeon for you that will hopefully make some of your players skin crawl a little bit. It is a dark place where they will not expect to end up and it is filled with all sorts of creepy crawlers. So tell the players with arachnophobia to stay home for this session, because your players are going into the Skin Crawling Caverns.
And remember that this adventure goes along with yesterday’s Blue Dungeon Thursday, so check that out too. I hope you enjoy.
Skin Crawling Caverns
A Cavern Dungeon Crawl for 4 Characters of Level 4 – 5
Below the surface there are many caverns and tunnel systems that run for miles. Underground rivers that flow through the rock, carving new paths as the centuries go by. In these winding and twisting caverns many creepy crawly creatures make their homes, waiting for any prey to enter their territory, so they can have their next meal.
Some of these caverns are closer to the surface than others, weakening the ground above and causing collapses and sink holes that lead into deep dark places where humanoids rarely go. There is a section of land on the surface that has a large cavern beneath it, and the earth has been slowly wearing away there, to the point where even the lightest step could set off a cave in.
Legendary Magic Item: While in a tavern a group of travelers are talking about some ruins to the North that supposedly house a long lost magical item with legendary powers. If asked about this, they freely talk about the location of the ruins in the forest. They will give any and all information needed to make the two day trek and even know a few details about the legendary magical item that could potentially be in there. But any who embark on this journey will never make it to the ruins, as the ground is weak and about to give way.
For the DM: Regardless of where your players are headed off to they will not make it there on this day. Instead somewhere along their travels, the ground will begin to shake and they will see the earth start to break up in a 40 ft. rough circle around them. They will all need to make a DC 16 Dexterity Saving Throw, on a failed save they will take 3d10 bludgeoning damage, half as much on a successful save as they fall deep into the earth, possibly to never be found again. They tumble with the crumbling earth down about 80 ft. landing in a roughly 50 ft. diameter cavern. Looking up they cannot see the surface, and attempting to climb out proves to be impossible as the ground is loose and crumbles away as anyone tries to climb out. If a character tries to fly out, they quickly realize that the ground collapsed in on itself at the surface and they are lucky to not be buried beneath the ruble.
Skin Crawling Caverns
Cavern Features: The tunnels and caverns are very roughly carved and appear to be naturally formed over time. Unless otherwise stated in the text, the ceilings of the tunnels are about 10 ft. high. The sound of running water can be heard through out the caverns and tunnels that wind through this underground maze and most of the areas are damp and cool. Any water in the caverns is fed from an underground glacier and is extremely cold, every round that is spent in the water requires a DC 15 Constitution Saving Throw, any creature that fails receives 1 level of exhaustion per fail. Each square on the map is equal to 10 sq. ft.
1. Starting Cavern: This is where the PCs find themselves after they fall into the earth. The cavern is about 50 feet in diameter and the ceiling goes up 60 ft. into darkness where the hole they fell through has caved in on itself barring any exit. A tunnel about 15 ft. wide leads out of this cavern to the North East.
2. 15 ft. Drop Off: In this roughly 20 ft. wide section of tunnel there is a 15 ft. drop off before the tunnel continues to the South East. It requires a DC 12 Strength (Athletics) Check to climb up or down this drop off, the DC is reduced by 5 if rope is used.
3. 20 ft. Drop Off: In this roughly 25 ft. wide section of tunnel there is a 20 ft. drop off before the tunnel continues to the West. It requires a DC 12 Strength (Athletics) Check to climb up or down this drop off, the DC is reduced by 5 if rope is used.
4. Large Cavern: This large cavern is about 70 ft. x 80 ft. and its ceiling rises up about 35 ft. There are two tunnels that lead out of this large space, one tunnel that leads to the East and another leading out to the South. The upper half of the cavern is covered in what appears to be webs.
This area has Four Giant Spiders and Five Swarm of Insects (Spiders) living in the Northern webs, the webs are considered difficult terrain to move through. They will go after anything that looks like food and will try to grapple and drag PCs into their webbing.
5. 15 ft. Drop Off: In this roughly 15 ft. wide section of tunnel there is a 15 ft. drop off before the tunnel continues to the South. It requires a DC 10 Strength (Athletics) Check to climb up or down this drop off, the DC is reduced by 5 if rope is used.
6. 30 ft. Drop Off and Water Filled Tunnel: This section of tunnel opens up slightly to a 30 ft. drop off before continuing on to a section of tunnel that appears to be flooded. It requires a DC 14 Strength (Athletics) Check to climb up or down this wet rocky drop off, the DC is reduced by 5 if rope is used. At the bottom of the drop off a narrow tunnel filled with water about 5 ft. deep leads to the East.
7. Cavern Map Carvings: The flooded tunnel leads into this large cavern that rises up 15 ft. about half way in and a path in the center leads up to the higher level. On the upper level there are crude pictures and words carved into the cavern walls and floor on the far East wall. The carvings have somewhat worn away and are barely legible. It requires a DC 14 Intelligence (Investigation) Check to read the words and drawings and figure out what they mean. The words count about 120 days that someone spent down here trying to find a way out. There are notes about specific sections of the caverns and it looks as though whoever made these carvings had found a potential way out in a long narrow cavern (area 19) with two passages leading in from the South and a large body of water that potentially leads to the surface. It also tells of an underground river system (area 10 and 22) that accesses different sections of the caverns through under water tunnels, the one who carved these words and drawings seemed to be confident that this was their way out.
There are Two Bulettes that have burrowed their way into this room, one is sitting up on the ledge where the carvings are located, the other is on the lower level. They will attack intruders, but are not looking for a fight, if one is killed, the other will attempt to flee the battle.
8. Four Way Intersection: This intersection has tunnels leading to the North East, North West, South East, and South West.
There are Two Ropers hanging from the ceiling above the intersection, they require a DC 12 Wisdom (Perception) Check to notice. If none of the PCs see them, they attack with a surprise round to start the encounter.
9. 10 ft. Drop Off and Underground River: This section of tunnel has a 10 ft. drop off before turning to the North. It requires a DC 10 Strength (Athletics) Check to climb up or down this drop off, the DC is reduced by 5 if rope is used. The Northern section of the tunnel has a 15 ft. wide and about 5 ft. deep underground river running down it that leads into a 1 ft. to 2 ft. high gap in the Southern wall of this tunnel. The tunnel itself leads North and gently bends around until it ends in a small chamber to the South.
There are Four Black Puddings located randomly around the river that runs through this tunnel, waiting for something to come for a drink so they can strike.
10. Underwater Tunnel Entrance Pool: The pool of water that feeds the river that runs through the tunnel connected to this small chamber is about 15 ft. wide and 20 ft. long. From the surface a creature with darkvision can tell that the pool is about 30 ft. deep, it requires a DC 15 Wisdom (Perception) Check to notice the tunnels about half way down. One of the underwater tunnels leads to the North East and the other to the South West, the current is moderate here and flows towards the South West. It requires a DC 15 Strength (Athletics) Check to swim against the current. The North East underwater tunnel is 40 ft. long and surfaces again in the shallow river in area 23, the South West tunnel is 60 ft. long and surfaces again in the large pool of water in area 24.
11. 20 ft. Drop Off: In this roughly 15 ft. wide section of tunnel there is a 20 ft. drop off before the tunnel continues to the West. It requires a DC 14 Strength (Athletics) Check to climb up or down this drop off, the DC is reduced by 5 if rope is used.
12. 3 Way Intersection: This intersection has tunnels leading to the North, South and South East.
There are Two Giant Scorpions making their way through the tunnels that are looking for food.
13. 15 ft. Drop Off: In this roughly 20 ft. wide section of tunnel there is a 15 ft. drop off before the tunnel continues to the South. It requires a DC 10 Strength (Athletics) Check to climb up or down this drop off, the DC is reduced by 5 if rope is used.
14. 20 ft. Drop Off into Cavern: There is a 20 ft. drop off before the tunnel continues into a large cavern that is 70 ft. wide and 40 ft. long with a 20 ft. tall ceiling. The room is filled with large webs that span the the entire cavern, the entire chamber is considered difficult terrain as the webbing is sticky and is not easy to traverse. The webs can be used to easily climb up or down the drop off requiring no check. There are exits from this chamber to the North where the drop off is located and another to the East through the webbing.
This area has Four Giant Spiders and Five Swarm of Insects (Spiders) that have made this chamber their home, they do not attack until someone touches the webs that cover this room. If PCs are specifically trying to traverse the room without touching the webs, have them make a DC 16 Dexterity (Acrobatics) Check to avoid the webs as they make their way through.
15. 20 ft. Drop Off: In this roughly 15 ft. wide section of tunnel there is a 20 ft. drop off before the tunnel continues to the North. It requires a DC 14 Strength (Athletics) Check to climb up or down this drop off, the DC is reduced by 5 if rope is used.
16. The Phase Spider Den: This large cavern is 70 ft. wide and 60 ft. long with a ceiling that goes up about 30 ft. There are sparse webs in this room, but most are close to the walls and dangle from the tall ceiling. There are exits to the South, North West and North East.
There are Three Phase Spiders living in this area, they will try to stay hidden and surprise any who dare to enter.
17. Horizontal Drop Off Separated Chamber: This chamber is 40 ft. wide and 60 ft. long, the ceiling here is 40 ft. high. There is a 15 ft. drop off in the centre of the room before the tunnel continues to the North. It requires a DC 14 Strength (Athletics) Check to climb up or down this drop off, the DC is reduced by 5 if rope is used. There are exits from this chamber to the North and South.
18. Vertical Drop Off Separated Chamber: This chamber is 45 ft. wide and 50 ft. long, the ceiling here is 40 ft. high. There is a 20 ft. drop off that runs the length of the chamber and the tunnel continues to the North. It requires a DC 12 Strength (Athletics) Check to climb up or down this drop off, the DC is reduced by 5 if rope is used. There are exits from this chamber to the North and South.
19. Underground Lake Chamber: This chamber is 95 ft. wide and 30 ft. long with a ceiling that rises up about 25 ft. There is a large body of water against the North wall of the chamber that is 60 ft. wide and comes out from the wall about 15 ft. a creature with darkvision can tell that this body of water goes down about 50 ft. It requires a DC 15 Intelligence (Investigation) Check to notice that toward the bottom about 40 ft. down there is a large opening. The opening is about 25 ft. wide and 15 ft. tall and continues to the North, this tunnel opens up to a lake on the surface after about 80 ft. and is a viable route to escape the caverns.
Under the water about half way through the underwater tunnel that leads out of the cavern there is a Giant Crocodile that will attack anything it thinks it can eat.
20. Umber Hulk Den: This room is located at the end of a narrow tunnel that enter from the North, it is 45 ft. wide and 40 ft. long, the ceiling of this room is 25 ft. high. The floor of this room is covered in animal carcasses, but there is no sign of what killed them or how they got down here. A DC 15 Wisdom (Perception) Check reveals a dead human among the carcasses, if the body is investigated the PCs will find that his coin pouch is intact and contains 25 PP, 50 GP, 25 SP, and 5 CP. The body also appears to be wearing +2 Studded Leather Armor.
There are Two Umber Hulks that have made this place their home and will burrow out of the walls as soon as a PC disturbs any of the carcasses.
21. Basilisk Chamber: This room is located at the end of a long 15 ft. tunnel, the tunnel that leads into this room from the South has a 10 ft. drop off about half way down. It requires a DC 16 Strength (Athletics) Check to climb up or down the slick drop off, the DC is reduced by 5 if rope is used. The room itself is 60 ft. wide and 70 ft. long, the ceiling rising up about 20 ft. In the center of the room is a large 35 ft. x 30 ft. pool of water. A creature with darkvision can tell that this body of water goes down about 30 ft. There are no underwater tunnel exits in this pool.
There are Two Basilisks that have taken up residence in this room, they appear to be working on creating a den or nesting area here. They are very territorial and will attack all who enter.
22. Underground River and Hook Horror Nest: This large room is about 110 ft. wide and 80 ft. long with a ceiling that goes up 40 ft. On the East wall there is a 20 ft. ledge that leads up to a platform. It requires a DC 13 Strength (Athletics) Check to climb up or down the ledge, the DC is reduced by 5 if rope is used. From the lower level a nest like structure can be seen on the higher level with a DC 15 Wisdom (Perception) Check. In the North West section of this chamber, there is a 15 ft. wide river that is being fed from a narrow hole in the North wall of the chamber and exits into a slightly larger hole on the East wall. The water is moving fast and a creature with darkvision can see that it is about 10 ft. deep. A DC 12 Intelligence (Investigation) Check reveals that the underwater tunnel on the East wall is large enough that a medium sized creature could swim through it. The current of this river is too strong to swim against. The Easter underwater tunnel surfaces again after about 15 ft. in area 23.
There are Two Hook Horrors in this room up on the ledge in the large nest, they are sleeping when the PCs enter the room. Neither can be seen when in the nest, if the nest is disturbed they wake up and attack.
23. Small River Chamber: This room is only accessible by swimming through the underwater tunnel to the north from area 22 or by swimming against the current from area 10, the current is too strong from area 22 to swim against. The small river is only about 5 ft. deep here, but the current is still fairly strong requiring a DC 10 Strength (Athletics) Check for a creature to hold its footing standing in the water. The underwater tunnel that continues South West can clearly be seen by any creature with darkvision.
24. Escape!: This room is only accessible from the the North East underwater tunnel that leads to area 10. The room is 70 ft. wide and 50 ft. long, but the ceiling here is only 5 ft. tall forcing any creature taller than 5ft. to have to squeeze. The room is entered through the 25 ft. x 30 ft. pool of water on the East side of the chamber, it feeds a small shallow river that leads exits the chamber through a tunnel in the North wall. The tunnel the water exits through is just high and wide enough for a single medium creature to squeeze through, after about 100 ft. of crawling through the tight passage in cold water (Constitution Save), it emerges in a forest on the surface.
When the PCs enter the room they will see that there is a snake mating pit here and Two Swarms of Poisonous Snakes, if combat break out here there are also Two Gricks in the exit tunnel that will join the combat at the end of round 1, otherwise they attack as the PCs try to make their final crawl to freedom.
Once the PCs emerge from the caverns, they will more than likely want to try and find the ruins or whatever it was they originally set out for. These ruins cannot be found and they will quickly realize that whoever sent them this way to find what they were looking for, lead them astray and there are no elf ruins in the area.
Download the DM Map HERE
Download the Player Map HERE
Hope to see you all back here for the next Free Adventure Friday! Until then, have a week.
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