Planar Bestiary
Psychic leech swarms have been known to infest astral ships, then hop off in search of better prey when the ship reaches a Material Plane world.
Predators of both mind and flesh, psychic leeches appear as many-stranded 3-foot lengths of glowing flesh, each ending in a horrific but different mouth, maw, or gruesomely toothed orifice. Alone, they are annoyances, but when dozens form a single swarm, they are a threat to be dealt with quickly.
The Astral Plane is a realm of the mind. In no way homogenous (as many assume), the Astral is instead highly stratified. One layer is the "Psychosphere," a region especially sensitive to psionic energy—so sensitive that the raw essence of the dimension is sometimes unconsciously molded into lifelike entities. The meanest, most base entities are psychic leeches, born of idle impulses not acted upon, angry outbursts that were bitten back, and murderous urges never consummated. The repressed negativity in all bordering realms seeds and feeds them, but worlds of the Material Plane are most responsible.
Psychic leech swarms are parasites drawn to those who travel through the Astral Plane. They also find their way to worlds of the Material Plane where concentrations of minds are especially high, like in large cities.
Motive: Spread misery, misfortune, and fear
Environment: The Astral Plane, worlds of the Material Plane in large cities, in groups of three to six
Health: 6
Damage Inflicted: Moderate wound (4 points)
Movement: Short; short when flying
Modifications: Spreads psychic inflammation as level 4
Combat: The dozens of bites of individual leeches making up a swarm count as a single attack each round.
A living creature injured by the psychic leech swarm that fails a level 4 Intellect defense task when the encounter is concluded is infected with psychic inflammation, a mental disease (see box).
If encountered on the Astral Plane, all the psychic leech's tasks are eased by two steps.
Interaction: Because psychic leech inception relies on the worst impulses of thinking beings, an attack by a psychic leech swarm can leave an imprint—a disease of psychic inflammation—long after the creatures themselves are driven back.
Use: The psychic leeches lurk in eaves, the shadowed heights of a vaulted ceiling, or along the top of the wall, until they drop down suddenly to head height and begin swarming.
PSYCHIC INFLAMMATION
This level 4 mental disease manifests after about a day, causing changes to the target's behavior. Changes begin with mild annoyance over small things, until every little thing makes the victim angry. When full symptoms set in after two days, the victim descends one step on the damage track. Thereafter, the victim must succeed on a level 4 Intellect defense task every time they are annoyed, disagreed with, or otherwise questioned. On a failed defense task, the victim attacks the source of their annoyance. The attacking victim can attempt another Intellect defense task each round to end that particular violent fit.
The disease can be cured by magic capable of doing so, or with rest; once the victim is showing symptoms, they can make an Intellect defense task after each 10-hour recovery roll; once the character racks up two successful defense tasks, they recover naturally (and ascend one step on the damage track).
GM Intrusion: A character traveling the Astral Plane is hit by a psychic leech swarm and immediately returned to the plane where they began the journey, or back into their own body if they were mentally projecting themself.