Mobile towers of flesh and bone followed by swarms of undead birds. Walking flesh mansions animated by tiny fiends. Demonic entities as likely to trap and hunt demons as they are player characters. These are the kakuen-taka, the Hunger That Moves.
To appreciate the kakuen-taka, you really need to see the illustration in the Inner Sea Bestiary of an insectile tower made of mammoth parts. While not one of my favorite images in general, it definitely captures the alien otherness of these evil outsiders. This isn't a vision of the Abyss by Gygax, Grubb, or even Albrect Dürer. These are reminiscent of the chitinous hulks of Dark Sun and the mantis-like angles of Planescape. This is Hell as conceived by Alan Moore and drawn by Todd McFarlane in the landmark Spawn #8. When your players spot these flesh mansion spires in the distance, they know they're not in Kansas anymore, or Middle-earth, or even one of the more well-traveled layers of the Abyss. They are in frontier country now—and they are alone except for the tiny fey that want to ride in their skins.
The prophecy was simple: Born of his father’s divine thunder, the god-blooded storm giant Bron was to march across the Plains of Vexation and free the imperial city of Thrain from its veiled master occupiers. But Bron never finished his journey, as he was speared through the heart and consumed by a kakuen-taka. To fulfill the prophecy and save Thrain, Bron’s body must be reclaimed from the flesh mansion of the kakuen-taka and his spirit called back from whatever dark road it currently wanders.
Velvet Night, a succubus-controlled layer of the Abyss, lies in ruins. Qlippoths pour into the layer via a black canyon and gangs of kakuen-taka dot the horizon. As demon fights fiend, the pleasure palaces of Velvet Night sit abandoned, just waiting for looters to help themselves to a lifetime of magical artifacts, exotic drugs, and blasphemous alchemical reagents. (It may be a short lifetime, however…)
Even the worm-riding tribesmen of the Sandstorm Sea avoid the Chittering Mounds. Most of the towering structures are filled with ravenous ankhegs or the wights of tengu monks. But sometimes the mounds themselves are alive—kakuen-taka flesh mansions preserved in the heat like mummies until their bhogas awake from hibernation at the scent of live prey.
—Inner Sea Bestiary 20-21
I’m not sure who gets the credit for this monster. The Introduction to the ISB ascribes it to Jason Nelson, but online all the references I find seem to come from Clinton Boomer’s 2008 RPG Superstar run. My guess is Boomer conceived of these flesh mansion-wearing monstrosities in 2008 and Nelson got tasked with polishing the entry up for the 2012 softcover.