Skulvyn

Skulvyns were aquatic, bestial demons with a strange, slowness-inducing aura. In the Demonomicon of Iggwilv, they were counted as a form of unintelligent, demonic wildlife.

Description
Skulvyns resembled large, streamlined lizards with snake-like heads hosting gaping jaws and bulging black eyes. They also had broad, clawed, flipper-like feet and four long tails ending in razor sharp spines, allowing them to propel themselves through the water with great speed.

Behavior
The animalistic skulvyns were unintelligent creatures (although slightly above the standards of ordinary beasts) constantly on the search for prey, both to consume and to torment.

Abilities
Skulvyn were capable swimmers, but were slow on dry land. In a fight, skulvyns could fight with their fangs or claws, but preferred to lash out with their many tail spines, leaving wounds that would continue to bleed until sufficiently treated or healed by magic.

However, the most disturbing ability of the skulvyns was their bizarre magical aura, which caused any non-skulvyns within to move terribly slowly similar in effect to the slow spell. Unless the victim mustered enough will to resist, they would be affected by the aura for the next few dozen seconds, and though the resisted aura of a certain skulvyn wouldn't be a problem for the rest of the day, individual auras had to be endured separately.

Combat
Skulvyns typically hunted in schools ranging in number from 2-12, and their usual method of attack was to swarm a single target all at once. After their victim was horribly wounded, they would swim away and watch with delight as they gradually bled out, using their slowing aura to remain just out of reach.

Ecology
Skulvyns were known to work under other creatures such as myrmyxicuses, and understood the concept of tribute. They could be found on the fiendish plane of Fated Depths and swimming in the River Styx, though they were loathed to enter the Shadowsea of Dagon due to the rumors of undying clouds of flesh-stripping pollution.

Skulvyns could be summoned by the summon monster IV spell.

Biology
Skulvyns had a keen sense of smell.