Scrions are large, batlike creatures immediately recognizable by their strange, glistening bodies. Their skin is thin and partially translucent, allowing portions of the skeleton, musculature, and even several internal organs to be seen through the flesh of the head, chest, and wings. In flight, this gives them an eerie, almost spectral appearance.
Scrions are remarkably fast but wildly erratic fliers. They inhabit the caverns and subterranean regions of Byzantium Secundus, particularly the tunnels surrounding Drown Town, though the species is not native to the planet. Scrions originally evolved in the vast cave systems of Shaprut. During the Diaspora, specimens apparently stowed away aboard Shaprutan ore vessels and established breeding populations on Byzantium Secundus.
Their survival is intimately connected to cylofungus, which forms their entire diet. Scrions consequently establish colonies only where large concentrations of the fungus can be found. Curiously, cylofungus is known to grow naturally only in material containing Scrion excrement. Whether the fungus originally evolved alongside the creatures or one somehow became dependent upon the other remains a subject of debate among xenobiologists.
Scrions aggressively defend both their feeding grounds and their breeding pods—soft, faintly luminous gelatinous sacs attached to sheltered cave walls. A colony that normally ignores intruders can become violently territorial if anyone approaches its fungus beds or nesting chambers.
Despite their appearance, a Scrion’s most dangerous defense isn’t its teeth or claws. When threatened, it produces an extraordinarily powerful high-frequency shriek that interferes with the human nervous system. Those caught within approximately 15 meters may experience intense disorientation followed by temporary blindness. Curiously, most alien species—and the tranquier—appear largely immune to the effect.
Scrion Shriek: Anyone susceptible within 15 meters must make a Calm + Vigor roll. Failure causes temporary blindness, lasting one turn for each victory point scored by the Scrion.
For Drown Town, I especially like the ecological relationship between Scrions and cylofungus. It means killing a colony to get rid of the dangerous creatures could inadvertently destroy the very fungus people were trying to harvest, giving them considerably more utility than simply being another cave monster.
CR 2
Large Sized Monstrous Animal
Hit Dice: 4d8+12 (30 HP)
AC: 20 (-1 size, +6 Dex, +5 natural)
Initiative: +6 (Dex)
Speed: 20 Ft., fly 40 ft
Attack/DMG: Bite (+5 Melee/1d8+4)
Face/Reach: 10 ft by 5 ft/5ft
Special Attack: Sonic Shriek
Special Qualities: Darkvision
Saves: Fort +7, Ref +10, Will +6
Abilities: Str 17, Dex 22, Con 17, Int 2, Wis 14, Cha 5
Skill: Listen +11, Move Silently +11, Spot +11
Sonic Shriek: This attack plays havoc with the nerves and sensory systems of their targets. Anyone with in 45 feet of the creature receives 5d6 subdual damage (Reflex save to half).