Planar Bestiary
Peripleths roam the planes alone, leaving a trail of fractured spacetime in their wake.
These wormlike aberrations are hard to make out through the spatial distortion they exist within, but it's hard to miss their horrific stingers, sizzling with plane-fracturing potential.
Kin to aboleths, peripleths (also called "dimension smashers") are ancient beings who recall a much different multiverse before the gods and, according to their own memories passed down through the ages, before the current planar organization grew so stratified. The modern cosmology, whether imposed by the gods (as peripleths believe) or simply how things evolved, is something peripleths rebel against at a fundamental level. Just by existing, a peripleth fractures nearby spatial geometry.
Motive: Disrupt planar cosmology, defy the gods
Environment: Anywhere spacetime is weak or resources can be leveraged to collapse dimensions
Health: 23
Damage Inflicted: Moderate wound (6 points)
Armor: 3
Movement: Short; short when burrowing or swimming
Modifications: Planar lore and resisting mental influence as level 8
Combat: The peripleth attacks twice each round with their stinger. Against a target suffering from incohesion (described below), the stinger inflicts an additional 3 points of damage (ignores Armor) from fracturing reality, and the peripleth regains 3 points of health.
As an action, the peripleth can selectively disrupt the planar cohesion of a target within short range, causing spacetime to twist, buckle, and fold around them. If the target fails an Intellect defense task, they take 6 points of Speed damage (ignores Armor) and lose some spatial cohesion. The victim falls prone each time they try to walk or run, but they can crawl. Each time the victim attempts a task or attack, they must succeed on an Intellect defense task. Otherwise, the action fails, bleeding into warped planar geometry or otherwise being nullified. A victim suffering from incohesion that crawls a short distance away from the peripleth can begin attempting an Intellect defense task each round to expel the twisted geometry afflicting them.
A peripleth can transfer themself to any location they can see or know about on the same plane of existence, or that they know about on another plane, once per day. When they do, either they leave behind an immediate area of fractured spacetime, or form an area of the same size where they appear. The fracture lasts for ten minutes and affects other creatures that start their turn in or enter the area as a spatial cohesion attack made by the peripleth.
Interaction: Peripleths can communicate telepathically, but their ancient, alien minds seem just as fractured and disjointed as the spacetime they leave in their wake. They see themselves as foes of all natural creatures and of the dimensional order of the multiverse.
Use: A mass of chaos, unleashed by accident at the school of wizardry, has been a local curiosity for decades. Recently, a peripleth found it, and decided they could use the chaos as a seed of planar destruction.
Loot: A peripleth may carry a few incomprehensible items, but with some study, they might be useful as cyphers. Example items include a twisted piece of metal that can produce a detonation (singularity) or a hazed, warped piece of glass that can produce a detonation (matter disruption).
GM Intrusion: The magic or other ability used against the peripleth rebounds on a character.