An Adventure for Every Monster - Crab, Giant

Frequency: Rare
No. appearing: 2-12
Armour class: 3
Move: 9”
Hit Dice: 3
Percentage in lair: Nil
Treasure type: Nil
No. of attacks: 2
Damage per attack: 2-8/2-8
Special attack: Nil
Special defences: Nil
Magic Resistance: Standard
Intelligence: Non-
Alignment: Neutral
Size: L (4’ + diameter)
THAC0: 16
XP value: 35 + 3/hp

This adventure takes place in shallow waters just off the coast of an area of wilderness. Some time ago, a ship carrying treasure was sunk, either by natural or unnatural means. Many of the crew were killed in the wreck or struggled ashore only to fall prey to the humanoid raiders who roam just inland.

The ship itself is about half a mile off the coast, a hundred feet down, lying upright. The loot is stowed in two compartments in the hold and is stored in chests. Water has seeped into most of them, ruining any items that would be spoiled by immersion. (the DM can decide who owned the treasure and where its original destination was)

All the party has to do to recover the loot is to find a way to descend the hundred feet, enter the wreck and bring the chests to the surface. Unfortunately, their efforts will be hampered by two things:

Firstly, there are two guardians aboard the ship. The crew knew about them but not what they were and the impact of the ship hitting the bottom and the effects of the sea water have opened their caskets; they are Underwater Mummies, much as their dry-land counterparts but their bandages are treated with a resinous pitch-like substance that renders them immune to the effects of immersion and gives them a horrible black colouration. Holy water and fire have no effect on them but neither do they have the rotting effect. They will attempt to grapple their victims and drown them or stun them into unconsciousness so that they will die in that fashion.

Secondly, the ship and the surrounding waters have become the hunting grounds of a pack of giant crabs. There are eight of them and they are quite vicious hunters, surprising on a 1-4 of a d6. Their territory extends out of the water and onto the beach, including some caves in the crumbling cliffs. Some of those caves have scattered bones, the remnants of the drowned sailors which have been dragged back to land and eaten by the crabs. A few pathetic coins or trinkets may be lying with the bones.

DG note – oddly enough, the Giant Crab does not seem to appear anywhere on the Outdoor Encounter Tables in the DMG, even the Marine ones. If the DM wants to roll up some encounters while the party work out a way of getting down to the ship, the Salt Water Shallow Waters/Coastal Waters/Small Inland Seas table can be used

01-02 Crocodile, Giant
03-10 Dinosaur
11-17 Dolphin
18 Dragon Turtle
19-20 Elf, Aquatic
21 Ixitxachitl
22-23 Koalinth (marine hobgoblin)
24 Kopoacinth (marine gargoyle)
25 Lacedon (marine ghoul)
26 Locathah
27-25 Man, buccaneer
36-63 Man, merchant
64-67 Man, pirate
68-70 Man, pirate (tribesman with small craft)
71-73 Merman
74 Nymph
75 Octopus, giant
76-80 Sahuagin
81-83 Shark, giant
84-86 Snake, sea
87-89 Triton
90 Turtle, giant sea
91-96 Whale, carnivorous, small
97-00 Whale, small


DG Note 2 - check this out for another take on the Giant Crab adventure. Cool picture too.