Blue Hole

A blue hole is a circular sinkhole that forms on the bed of the sea in shallow water. The deep blue water of the hole creates a stark contrast with the lighter color of the shallow water that surrounds it.

d6	Depth	Width
1	about a hundred feet	about fifty feet
2	a couple hundred feet	about a hundred feet
3	about 500 feet	a couple hundred feet
4	about 1000 feet - dim light	nearly a thousand feet
5	about 1/4 mile - midnight dark	-
6	a mile or more - pitch black	-

To determine what you find at the bottom, either roll d8 twice on the following chart, or roll a d6 for each category separately.

d8	d6	You find...
1	5+	shipwreck
2	5+	treasure
3	3+	monster
4	4+	intelligent creature
5	6	ruins
6	3+	exotic flora
7	6	magical effect
8	-	roll again twice

d4	Shipwreck
1	a galleon laden with gold, but haunted by a jealous guardian
2	a warship with punctured hull, but weapons intact - an important secret lies within
3	an ancient yuan-ti pleasure barge with a magical device that still functions... erratically
4	appears to be a pirate ship, but is actually a gargantuan Mimic

d4	Treasure
1	a bed of giant clams, 1d6 of which hold melon-sized pearls worth 1000gp each
2	an exquisite marble statue lies half-embedded in sand
3	you spy the glint of metal - a magical weapon clutched tightly in the hands of a skeleton
4	a massive pile of coins, jewels, and other riches lie conspicuously gathered here... best be gone quickly, before whatever creature lairs here returns

Monsters and Intelligent Creatures by Depth

• For depth 1 or 2, roll d12
• For depth 3, roll d12+d4
• For depth 4, roll d12+4
• For depth 5, roll d10+8
• For depth 6, roll d10+10

d20	Monster	Intelligent Creature
1	swarm of quippers	merfolk
2	reef shark	aquatic oracle
3	electric eels	aquatic druid
4	the drowned	hag
5	giant octopus	sahuagin
6	giant shark	drowned master
7	plesiosaurus	dragon turtle
8	aquatic chimera	ghost
9	specters	flumphs
10	stone golem	crystal dragon
11	mimic	emerald dragon
12	chuul	topaz dragon
13	purple wurm	amethyst dragon
14	sea serpent	aboleth
15	dragonbone golem	marid
16	skum	storm giant
17	aquatic intellect devourers	sapphire dragon
18	aquatic umber hulk	elder brain
19	anglerfish	star spawn emissary
20	death kiss squid	kraken

d4	Ruins
1	a small merfolk town that has been ransacked and desecrated
2	an ancient yuan-ti bathhouse - but what is it doing down here?
3	a temple dedicated to some ancient dragon deity - iconography of Sardior
4	a metallic vessel of some sort... almost like a ship, but enclosed... there is breathable, if stale, air inside

Exotic Flora

• list

Magical Effect

• list