A necrophidius is a construct and there are several ways to go about creating one. First, the basic materials must be assembled: the skull of a cold-blooded murderer who has been killed within 72 hours of the ritual and the complete skeleton of a giant snake. The process will also require 10 days plus the services and laboratory of an alchemist, who will charge his or her full monthly fee plus 500 gp per hp of the completed necrophidius. At the end of 10 days, the potential owner has 24 hours to complete the ritual by one of the methods detailed hereafter;

First, a magical book can be used. These work the same way as a manual of the golems (q.v.) can be used to create a golem. Second, a high level magic user can cast the following spells in this order upon the pre-necrophidius alchemical mixture: limited wish, geas, and charm person. Upon completion of the charm person spell the death worm magically assembles from the various parts, absorbing the fluids of the mixture. Last, a cleric can cast the following divine spells upon the pre-necrophidius alchemical mixture in this precise order: quest, neutralise poison, prayer, silence 15-ft radius, and snake charm. As with the magic user, when the last spell is completed the necrophidius magically assembles from the various parts, absorbing the fluids of the mixture.