Sartan tanninim are a possible inhabitant of a strange-larva-hellish seal. They are not particularly threatening, mostly notable for high potential attribute drain in melee, somewhat notable melee damage, and high AC and DR.
While afflicted with the rotting, characters will occasionally create stinking clouds and suffer from reduced charisma (1 point penalty per 5 points of sanity lost).
Tannin (plural tanninim) is an ancient Hebrew word meaning "sea monster" (or sometimes "serpent," and sometimes translated as "dragon"). Ancient Semitic religions used sea monsters to symbolize primordial chaos, and sometimes evil (see also Tiamat/the Chromatic Dragon).
Sartan is a Hebrew word meaning "crab."