Giant leech

Giant leeches were a monstrous variety of the mundane, segmented worms of the same name.

Description
These creatures had slimy, slug-like bodies that were either mottled brown or tan in hue, or occasionally gray. Their bodies measured in length and had two antennae that protruded from their mouths. They had a round, sucker-like orifice for a mouth that allowed them to attach themselves to their prey.

On land these creatures moved very slowly in an inch-worm fashion, stretching forward and forward and attaching its anterior disk to the ground before doing the same with their posterior disk. They were even capable of climbing vertical and overhanging surfaces. When swimming however, giant leeches moved at a rapid pace and their bodies undulated vertically.

Behavior
Giant leeches never attacked for the sake of self-defense, only to feed. Whenever injured, they would attempt to flee the area.

Biology
Being an invertebrate species, giant leeches could squeeze their bodies through very small spaces. Even those who were rather larger were capable of this feat.

Senses

 * Sight: Like many species of invertebrate, giant leeches had a set of ocelli in place of normal eyes. These were a group of light receptive cells that could register changes in light intensity, though not actual images. Because of this, giant leeches often reacted to changes in nearby light.


 * Scent: Giant leeches had a keen sense of smell and could easily home in on or avoid certain creatures or substances, such as a bleeding animal. Their smell senses were sensitive to certain chemicals, even in small amounts.


 * In Water: Giant leeches were very sensitive to vibrations, easily becoming restless, and would attempt to locate the source of the disturbance. They also were sensitive to traces of metal in their water, with copper being the most fatal.


 * When Feeding: When attached to prey, giant leeches were unresponsive to most outside stimuli. The presence of ashes, fire, dehydrating substances, and especially salt would make them quickly release their grasp on a creature. They were highly vulnerable to salt and the application of sufficient amounts could even kill them. Because of this, giant leeches generally avoided surfaces covered in the mineral.

Saliva
Giant leeches had viscous saliva that was hard to remove without alcohol or a similar liquid. Their saliva had anesthetic properties, making it so that the creatures they attacked felt no pain and thus ensured they went unnoticed. This effect of their saliva was felt by their prey immediately upon contact.

The saliva of these creatures also contained an anti-coagulant and a substance known as a vasodilator that would enlarge blood vessels near wherever they bit. These induced a state of increased blood flow in their prey, ensuring that blood continued to flow from their bite for a duration longer than that of a normal wound. Their saliva also contained antibiotics, which made infections from their bites a rare occurrence.

Additionally, some varieties of giant leech had a substance within their saliva that would dissolve any pre-existing blood clots. When inside their digestive tract, blood did not coagulate.

Reproduction
Giant leeches were a hermaphroditic species, though they could not fertilize their own eggs. Some species laid them in cocoons, which they would attach to something underwater or bury within ooze. Others were known to carry their eggs around in a membranous sac on their underside.

Combat
These creatures took a stealthy and relaxed approach to hunting. Resting their bodies upon underwater plants and objects, or hiding within the mud or slime typical of their habitats, and waited to strike upon any prey that came within of them. They sucked the blood from creatures they attacked and were only rarely noticed. Those bitten by giant leeches had a moderate chance of contracting some form of disease, in particular red ache.

History
In 1357 DR and up to 1368 DR, giant leeches could occasionally be found in the sewers beneath Waterdeep.

Around the 14 century DR, a healer in Skullport by the name of Leech employed tamed giant leeches to remove poisons from peoples' bodies.



Diet
Much like their smaller counterparts, giant leeches primarily ate blood. Though some species were predacious, eating animals such as frogs and eels, and even the parasitic variety would engage in such eating habitats on occasion. Beyond that, there were some species of giant leech that fed upon carrion.

They generally hunted at night or whenever it was raining, in order to ensure that their bodies stayed moist. Once fed, they could go a whole month without feeding again and they could not be convinced to consume more once full. Because of this, they tended to shelter themselves after eating in a secure place where they could remain inactive for a period.

Habitats
These creatures were only known to be found in the waters of swamps and marshes.

In Faerûn, they inhabited the Mere of Dead Men, the Great Swamp of Rethild, the temperate swamps of Cormyr such as the Vast Swamp, temperate areas of the Sea of Fallen Stars, and the Lake of Steam. They were also quite prevalent in the marshes of High Moor, where they were found hunting in packs.

In the Unapproachable East, giant leeches could be found within the Umber Marshes of Aglarond.

Beyond Faerûn they inhabited the swamps of the Kutuk Valley in Shou Lung, the swamp Shibinuma in Kozakura, the many swamps of Maztica, and the island of Djinni's Claws. Beyond Toril, they inhabited the marshes and swamps of the planet Oerth.

Relationships
Giant snapping turtles and giant gars were two of many animals known to prey upon giant leeches. Of more intelligent creatures, kobolds were occasionally known to hunt down and roast them on a spit like one would a lamb. Some claimed that bullywugs within the Mere of Dead Men would use them as mounts.

Some swamp-dwelling creatures would use spider webs to help bites from giant leeches to clot faster.

Some nereids were known to keep giant leeches as pets.

Usage
Some creatures would hunt down giant leeches, seeking to make poisons from their saliva. Others used them as containers for blood, since the substance didn't coagulate inside their digestive trat.

Appearances

 * Adventures
 * The Shattered Statue • Dungeon #30, "...And a Dozen Eggs" • Ronin Challenge • Nightmare Keep • Dungeon #69, "Slave Vats of the Yuan-Ti" • Dungeon #72, "Mistress on the Mere"


 * Video Games
 * Eye of the Beholder