(chaotic, extraplanar, incorporeal, protean, shapechanger)
Source: Bestiary 6, pg(s). 214
Pelagastrs are able to bind themselves to corporeal beings like possessing ghosts, which they use to savour the physical world with as many senses as possible. Their tails can dip into reality so they can carry treasures from the physical world that the pelagastr's incorporeal form is otherwise unable to move.
Like voidworms (and unlike most other protean castes), pelagastrs are spawned from the chaos of the Maelstrom itself and are neither formed from lesser proteans nor from petitioners. Some claim they are intentionally created by a protean lord or keketar cabal. Pelagastrs generally cannot evolve into any other caste, though imenteshes tell of choruses of incorporeal keketars in service of the incorporeal protean lord Il'surrish.
Pelagastrs enjoy interacting with the physical world and are fascinated by even the most mundane experiences, whether they be pleasure or pain. Unrestrained by a physical body, they spy on private spaces and secrets. They do not consider their actions as violations of privacy that may ruin relationships or lives, but rather as wondrous gifts shared with lesser beings.
Pelagastrs rarely interact with keketar cabals and are most often seen near the borders of the Maelstrom with the rest of the Outer Planes, or in the Inner Sphere if possible, where they often make themselves enemies of genies, especially efreet who often ban them from their territories or kill pelagastr trespassers on sight; despite this, more pelagastrs always follow to begin new revels. In the Material Plane, they delight in running amok with little to no regard for the consequences of their actions. Scholars speculate the Maelstrom's currents of chaos disperse them far and wide.
Pelagastrs occasionally find like-minded hosts willing to be merged, mingling their memories, desires and bodily control. Harbouring a pelagastr (whether willing or not) inscribes a subtly chaotic stain on one's soul, potentially causing their children or grandchildren to be born as ganzi.
Pelagastrs are easy to summon but extremely difficult to control by spellcasters, often wreaking havoc, ignoring their masters' orders, rearranging their belongings or jumping from body to body. The social and legal ramifications of being possessed by pelagastrs gives them a reputation for being more trouble than they are worth.