Sssp was a Northern Mustafarian inhabiting Mustafar during the Imperial Era. In that time, Sssp belonged to a scouting party dispatched to investigate a crash site nearby, a matter of concern for their clan leader, Father Kkkt. At the site, the group encountered the Sith Lord Darth Vader, who possessed the haunted Mask of Lord Momin. The Dark Lord assaulted the Mustafarians, and Sssp was captured to serve as a vessel for the spirit of Darth Momin. After one of Momin's blunders, Vader executed the Sith's host body as retribution, thus ending Sssp's life and requiring the two Sith Lords to find a new host.
Sssp, a Northern Mustafarian, was a member of a clan on Mustafar under the leadership of Father Kkkt. In 14 BBY, Father Kkkt, along with another Mustafarian named Zzzs, observed a fiery object plummeting to their planet. Concerned, Kkkt tasked Sssp, Bbbl, Rrrn, and another Mustafarian with investigating the area and reporting their findings. Unknown to the clan leader, the fiery object was actually the burning ship of the Sith Lord Darth Vader, who intended to establish his fortress on Mustafar.
Much to the Mustafarians' surprise, their search uncovered no evidence of a crash. Sssp surmised that the wreckage must have fallen into one of the lava flows and disintegrated. Sssp suggested that the minerals from the dissolved wreckage would eventually be harvested, and that the group should return to Father Kkkt with nothing to report. However, before they could head back, the group was confronted by the Sith Lord Darth Vader and the Mask of Lord Momin. Bbbl and the fourth Mustafarian were immediately killed, while Rrrn managed to escape on a lava flea. Sssp was seized by the Dark Lord and compelled to wear the Mask of Lord Darth Momin, enabling the ancient Sith to take possession of Sssp's body.
As the host for the Sith Lord Momin's spirit, Sssp was deprived of control over his physical form. Momin exploited his new body to formulate the design blueprints for the fortress Vader and Momin planned to erect above a Sith cave situated on the Gahenn Plains. The intention was for the fortress to harness the Dark Side locus within the Sith cave and create a gateway through The Force that would reunite Vader with his deceased wife.
Momin's design ultimately failed, as Vader's attempt to open the doorway resulted in the fortress's destruction. Momin revised the structure's design four more times, each time with the same catastrophic outcome. By the fifth failure, Vader had grown impatient with the Sith spirit and, as a form of punishment, terminated Momin's host body, which also killed Sssp, leaving Momin in agony and without a host.
Sssp, a Northern Mustafarian, was a member of Father Kkkt's clan. Like most Northern Mustafarians, Sssp was taller than the majority of Southern Mustafarians. Sssp was doubtful of Kkkt's claims regarding a fiery crash, and was quick to dismiss them as paranoia when no evidence of a crash was discovered.
Like other Mustafarians, Sssp wore protective armor and a breath mask to shield against Mustafar's intense heat. Sssp carried a Mustafarian blaster rifle and rode a lava flea during the search for Vader's ship.