A child born from two Goa'uld hosts. This is considered forbidden by the Goa'uld System Lords because the Goa'uld genetic memory is passed down to the offspring, making the child a threat. (Goa'uld reproduce their own kind asexually.) The Harcesis possesses all the knowledge of the Goa'uld who fathered it.
Some time later the child, artificially aged, appeared on Abydos. He was taken by SG-1 to Earth to be interrogated in an effort to find out what he knew about the Goa'uld and their technology. However, the child took the opportunity to show Daniel Jackson what could happen if the information the S.G.C. sought was given to them.
Secrets - Daniel Jackson delivers the child of Apophis and Sha're, and hides the infant from Apophis on Abydos.
Forever In a Day - Amonet returns to Abydos for the Harcesis child, sending him into hiding with one of her handmaidens on the planet Kheb.
Maternal Instinct - Daniel Jackson allows the ascended Oma Desala to take the Harcesis where he can be safe.
Absolute Power - Artificially aged several years, the Harcesis, Shifu, emerges from the winds of Abydos to teach Daniel that the Goa'uld genetic memory is not something that can be taken advantage of.