Source: Inner Sea Bestiary, pg(s). 47
Chemnosit, also called Great Doom Chemnosit or the Monarch Worm, is one of the Spawn of Rovagug, and is among the four spawn best known on the continent of Avistan. When it arrived is unknown, except that it escaped the Pit of Gormuz after the great beetle Ulunat. After breaking free from its prison, Chemnosit burrowed into the Darklands, where the urdefhan in Orv and certain of the more debased humanoids there worship it. On occasion the drow and duergar of Sekamina have called it up, usually to the ruin of their settlements. Svirfneblin have also witnessed it, but perhaps not (yet) in their own domiciles. The book Way of the End-Name includes a description of the beast, stating that "it rears up like a snake about to strike".
Chemnosit is not known to be deceased.