|Lobster's head, or a black pearl|
|Divine Rank||Intermediate God / Demon Lord|
|Domains||3E: Destruction, Evil, Water
|Home Plane||Fated Depths (Abyss)|
|Worshippers||Kuo-toas, undersea creatures|
|Favoured Weapon||Pincer Staff|
Blibdoolpoolp, aside from sounding like one of the stupidest onomatopoeiae you've ever heard, is most recognizable for being one of the most minor racial deities in Dungeons & Dragons. She is the Chaotic Evil patron goddess of the Kuo-toa, a race of insane fish-men who can basically be described as the Deep Ones' slightly retarded redneck cousins from the Underdark. She is best known for appearing as a beautiful naked woman with the head of a giant lobster and lobster claws instead of hands.
In 5th edition, it's been suggested that Blibdoolpoolp was probably first created by a mad Kuo-toa finding a statue of a woman with the head and arms broken off, replacing them with the appropriate parts from a giant lobster, and madly believing its creation was a god, which spread like wildfire through the race. This is because making up fictitious gods as a result of their insanity is one of the defining "quirks" of the kuo-toa in 5e.
Kuo-Toa as a society are really freakin' religious and pretty darned xenophobic too just like another civilisation we know. Their priests get all the significant power in their communities and deviation from established religious doctrine or acknowledgement of any god other than the god the rest of the community worships is considered abominable Heresy which is liable to get one killed.
Blibdoolpoolp demands constant veneration and regular sacrifices, and isn't particularly choosy about where the sacrifices come from, so Kuo-Toa who become lax in their devotions are at risk of getting sacrificed themselves. Therefore Kuo-Toa worship Blibdoolpoolp because they often have no other choice.
Those rare cases where Kuo-Toa don't worship Blibdoolpoolp is because their community simply hasn't even heard of her. But that doesn't change the group propensity to mob together and worship only one god, while executing heretics and offering sacrifices. These other groups tend to gravitate towards Dagon whose doctrine is almost identical to Blibdoolpoolp.
Inquisitors of the Drowning Goddess
As mentioned, communities which venerate Blibdoolpoolp are constantly on the lookout for heretics within their own midst. This prestige class represents individuals who make it their business to find those deviants and bring them to "justice".
Typically starting as Monks, these individuals are always Lawful for some reason, which is at odds with worship of a chaotic deity. But in any case, they don't cast spells, so it doesn't really matter.
They gain a Fear Aura along with an increasing bonus to their intimidate and sense motive skills; they also gain the ability to create adhesives which improve grapple checks to subdue opponents, making them true Inquisitors. At later levels, they gain a resistance to mind influencing effects and illusions.
Their final ability is hilarious: they can cover themselves with glue which causes them to stick fast to anything they touch, allowing them to dogpile opponents into submission. The strange thing is that the glue only works one time before it needs to be renewed, so it can be easily rendered irrelevant by throwing a penny at them such that it gets used up!
Sea Mother Whip
Blibdoolpoolp makes her realm somewhere in the Abyss. Which layer exactly is a bit of a mystery, because it is never actually provided and any information found between campaign settings is incompatible with each other.
In the Forgotten Realms, she resides in the Fated Depths, which she shares with the deity Sekolah, though the two are at constant war with one another, though Blibdoolpoolp is believed to be losing the conflict and is at risk of declining into irrelevance. However, Sekolah's own part of the realm is accessed from the frozen layer of Stygia in Baator. This implies that the realm of the Fated Depths is a direct link between the Abyss and the Nine Hells.
What's more complicated is that the Fated Depths are considered an end point for the River of Blood which is analogous to the River Styx, which otherwise normally ends (or begins) in Acheron.
Meanwhile, back in the core cosmology, Blibdoolpoolp is occasionally referred to as a demon lord instead of a deity. It may be that Blibdoolpoolp is actually an aspect of the Demon Lord Dagon, who has existed and been worshipped by Kuo-toas since long before Blibdoolpoolp ever came along, and is also at war with Sekolah, marking some points of similarity between Demon Lord and Deity. Furthermore, Dagon cultists are also attempting to wipe out worship of Blibdoolpoolp, so it may be that the religion just gets absorbed into the worship of Dagon.