Shen

Notes:
 * Spawned by trading a Shrimp Lantern to the ??? at the southwest corner of J-9.
 * About 45 seconds into the fight (or sometimes once it reaches low HP, even before that) Shen will summon two Shen's Filtrates; at this time Shen also retreates into his shell for the first time, which regens HP. It is possible to kill Shen quickly with a full alliance of characters who have full TP, and use weaponskills and cast on Shen to do the most damage immediately at the start of the fight, to defeat it before the Filtrates spawn.
 * Shen's Filtrates are two Water Elemental NMs; they are resummoned throughout the fight if killed, and automatically attack whoever Shen has hate on. Special attacks from the Filtrates include 120-150 damage melee hits; fast-cast of Flood, Waterga III, Water IV. The Filtrates are immune to Stun, Silence, and Bind but can be slept. Alternately, you can kite Shen and the Filtrates if Shen is not killed before they spawn.
 * Around 20,000HP
 * Special Attacks: Regular Uragnite special attacks (goes into Shell, during which it cannot be attacked, and regens HP), very high damage AOE poison; Spike special attack (over 1000HP direct damage); Suctoral Tentacle (Bind); Immune to Silence; casts Water IV, Waterga III, Flood, Drown
 * Killable by: 18 level 75 characters
 * Reverend Mail is a 100% drop.

Historical Background
It is not clear what Shen is in mythology or folklore, but there are a few possibilities. One possibility is Shen refers to the Chinese word shen. Another possibility is that Shen is a mistranslation of Chan. In Chinese mythology, Chan was a giant clam, a sea monster living in the ocean. Its "out breathing" would cause coral reefs to be shaped and transformed into amazing palaces. [needs corroboration, only one account was found]

In Chinese, shen can refer to a person, sash, to stretch, to groan, Orion's Belt, deep, or as a character to indicate something personal or pertaining to a human (shēn), sacred (shén), to investigate, aunt, juice (shěn), scrupulous, to seep in (shèn). In Chinese, chan can refer to leading by the hand (chān), an insect-like animal, a cicada, a weak person, to tangle, crafty, the sound of flowing water, a plot of land (chán), product, shovel, to destroy, to clarify (chǎn), to tremble, or to repent (chàn). Combining the 2 characters, shenchen means "deep". It seems the most likely meanings are "deep" or "sacred" (shén is a character placed with other characters can denote something sacred, holy, or supernatural, like a priest, holy man, child prodigy, or mysterious, mythical) based on it being a shelled sea creature that drops a piece of gear for WHM.

In Ancient Egypt, the Shen Ring was a symbol which was a circle with a tangent line running through its base. It represented eternity. Shenu was the Egyptian word for "encircle".

Shen, a Chinese word for spirit or soul, is often referenced in Taoist and Traditional Chinese Medicine literature. During the Ghost Festival, a traditional Chinese festival and holiday, which is celebrated on the 14th night of the seventh lunar month, the Chinese honor their ancestors by, among other activities, releasing miniature paper boats and lanterns on water, which signifies "giving directions to the lost ghosts."

[if anyone knows for certain what Shen is or if this Shen is related to any of the provided meanings, i.e. why is it a shelled mollusk that preys on a shrimp toy, please add to this entry]