Apophis' mothership was the flagship of Apophis' fleet.
First seen after Apophis took control of Sokar's forces, the vessel possessed many advantages over the standard Ha'tak: it was larger, possessed a faster hyperdrive, and had weapons which could incinerate a Ha'tak in six shots. (SG1: "The Serpent's Venom")
Apophis also took it and his fleet to Vorash in an attempt to destroy the Tok'ra. The supernova of Vorash's sun sent Apophis' mothership into another galaxy, along with SG-1. While there, the vessel was boarded by Replicators, who overran the ship, but Apophis set the self-destruct and escaped in a Tel'tak. The Replicators were unable to deactivate the self-destruct, and the ship was destroyed. (SG1: "Exodus", "Enemies")