Flukes

"Crushing black silence. Thoughts like mud. Focus on light. Recall the surface. Recall the Surface! You are human. Three great presences. Deep as stone.

"The Drowning Feast. The greatest yet. Dishes like treasures. Gifts from above. Gold, wood, brick. Flesh, hair, eyes. Words, rhymes, thought. Why remain below? Flee far above. The wrong place. The wrong time. Abandon your plan. Or be resolved.

"The oldest Lorn-Flukes. Too vast now. Swollen with hate. Swollen with wisdom. Tendrils glisten dully. Light contracts nodules. Watch them flex.

"WHAT HAVE YOU BROUGHT US? Voice in bones. Words in water. Answer in haste. They are hungry."

Look at all those spikes. Art from SS.

Flukes are monstrous, possibly primordial creatures that appear to be giant sea urchins. Their species can vary largely in size (see below). They can be pretty friendly all things considered, hanging out around Flute Street, and they're responsible for the creation of the Rubbery Men.

However, there lurk Flukes in the waves of the Unterzee, that even the most grizzled zailor will hesitate to speak of. These Lorn-Flukes can easily overwhelm ships, both by physical destruction and by terrifying the crew by speaking words of Correspondence. As the splinter faction of the more mundane Flukes, they are enemies of the Masters and seek to control or destroy the Bazaar. There are many other varieties of Flukes that menace the zee, such as the Dawn-Flukes, Lorn-Flukes that fell under the spell of the Dawn Machine, and the Lornest-Flukes, found only in the blackest of depths.

There is a captive Lorn-Fluke in the Cave of the Nadir.

Veteran zailors who hoped to escape the Flukes upon crossing the Avid Horizon will be sorely disappointed as certain Flukes have taken to the skies as exiles of their kind. These Scorn-Flukes are even more dangerous than their Neathian counterparts, and they're beyond furious, screaming the Correspondence with unprecedented fluency at hapless locomotives as their ritualistically scarred bodies undulate through the star-maddened skies...

A Scorn-Fluke is responsible for the strange, grotesque, and honestly hilarious phenomena at Worlebury-juxta-Mare.

A few more interesting spoilery snippets

When killed, lorn-flukes leave behind a core which glows irrigo, the colour of forgetfulness, and is made of the souls of the creature's victims. It may be possible for individual humans to be transformed into Flukes as well. The Flukes as a whole are actually from the planet Axile; they are also formally called Axiles. It's hinted that a certain Master may be responsible for bringing them to the Neath...

Art from FL