Spiders’ Cavern – an encounter for 5e

This is an encounter I created for the Darokin adventures, but it is completely generic. It adds an interesting 3D aspect to the encounter. The group were guarding a caravan along a wilderness trail, and I was introducing a new player. This was set up as a rescue scenario for her.

It is based on the Spider Lair from the Geomorphs Cavern Lairs pack by the amazing Heroic Maps.


Suddenly the ground gives way beneath two of the guards at the front of the caravan and they fall with a scream. As you rush forward, you see the trailing edges of the leaf-mould covered cobwebs which had­ disguised the hole, and darkness…


There is a spider lair underneath the road here, and <player character> and Dragano (an NPC guard) have fallen in.

There is no light down here other than what seeps through the webs from room 1.

1 Landing cavern

There is a 30’ drop through webs to the floor of the cavern. Anyone falling should roll d20 to see how far they fall and whether they get caught by the webs part way.

1-3 Caught 5’ down – can reach a hand or stick
4-6 Caught 10’ down – can reach a long pole
7-9 Caught 15’ down
10-12 Caught 20’ down
13-20 Fall to bottom, taking 1d6 damage

Characters which are caught are restrained by the web. They can burst free from their section with a DC12 strength check, dropping 5’ if they succeed.

Characters who have only fallen 5’ can be pulled free with a DC10 strength check and any sort of pole.  Characters who have fallen further need a rope and the DC increases by 5 for every 5’ distance. The webbing can also be cut with slashing or fire damage – AC10, hp 5/5’, vulnerable to fire, immune to bludgeoning, poison and psychic damage. Each 5’ section cleared reduces the DC by 5 again.

Dragano is caught 20’ down and needs rescuing. Stephanie is as per her roll.

The webs stretch to 4’ above the ground, so anyone except a halfling will need to bend over or risk getting tangled again. This means the room is difficult terrain, and they attack with disadvantage.

There are 3 giant spiders here.  The first one arrives after d4+1 rounds, with the other two in the next d3 rounds.  If there is anyone on the ground they will attack them first with web then try to bite, otherwise they will attack from the bottom up, working together to try to immobilise each in turn.

They will retreat if reduced to 25hp or fewer, waiting for their web to recharge.

2 Brood nest

This cavern is roughly 15’ high and filled with webs along most sides.

The north-west corner contains the wrapped corpse of a fighter in furs and leather armour with studded leather arm-guards. He has a large crop of blond hair and a blond beard braided into a fork. One arm is twisted beneath his back. He has been sucked to a husk. Beneath him lies a war hammer, and there is a hand axe at his waist.

The south-east corner contains the wrapped bodies of two gnolls.

There are 3 young giant spiders (see below) in this room plus many recently hatched (2 swarms). They will be attracted by the sound of movement, thinking it is food brought by their parents.

The floor is scattered with broken weapons and armour and assorted bones. In among them can be found d6 gems: 2 moonstones (50gp), a tiger eye (10gp), a jade (100gp), a sardonyx (50gp) and an eye agate (10gp), 3d6 cp and d8 sp.  There are also 2d4+3 flasks. One contains a potion of healing, the others are empty.

3 Larder

There are 2 goblins wrapped up and trapped here.  They are alive but unable to escape their bonds.

4 Exit

There is a carrion crawler on the ceiling which drops on anyone who tries to go this way.

(This was basically to stop them trying to explore further into the cavern complex – but feel free to expand here…)

Giant Spider Young

9 (-1) 17 (+3) 10 (+0) 2 (−4) 9 (-1) 4 (-3) 13 5
+3 9

Skills: Stealth +7, Blindsight 10′, Darkvision 60′, Web sense, Web walker, Spider climb
Action: bite: +1, d4-1p + d6 poison (DC9 CON for half)

Based on giant spider.

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