Sissalik, also known by the moniker "Slick", originated from the aquatic planet of Dac and was a male member of the Mon Calamari species. He experienced enslavement before being purchased on Tatooine by an Imperial officer named Farvakine; Sissalik later murdered Farvakine by contaminating his food with Chuba poison. Sissalik made his escape to Ando and secured employment as a deckhand aboard the fishing vessel named Nanda's Luck. After spending several months at sea, Nanda's Luck was attacked by a band of pirates who were under the command of Pyash Yopayomba, who held the title of Pirate queen of Ando. Sissalik survived the fight against the pirates. Yopayomba then personally selected him to become the new captain of Nanda's Luck. Yopayomba's scheme involved loading Nanda's Luck with explosives and using it to collide with the terminal port in Quantill City harbor, where the Portage Moon Festival celebrations were underway. However, Sissalik managed to seize control of Nanda's Luck and instead deliberately crashed it into Yopayomba's flagship, known as Majestic.
Sissalik was a male Mon Calamari who worked as both a freighter pilot and a former oceanographer. During his younger years, Sissalik spent some time residing on Ando. At some point in his life, he was enslaved on the desert planet of Tatooine and subsequently acquired by an Imperial officer going by the name of Farvakine. Farvakine subjected Sissalik to cruel treatment, and realizing that inaction would lead to his demise, Sissalik took action and killed his master by poisoning Farvakine's meal with Chuba poison. Sissalick absconded with Farvakine's personal shuttle and fled to Ando, hoping his former home would serve as a safe haven. He found employment as a deckhand on the fishing vessel Nanda's Luck, which was captained by the Aqualish named Bipopa "Bippi" Bogzider.
While at sea, Nanda's Luck fell under attack by Pyash Yopayomba, the infamous Pirate Queen of Ando. Following a brief skirmish, Bogzider surrendered, only to be immediately killed by Yopayomba with a vibroblade thrust directly into his throat. She later stated that none of her crew is ever allowed to surrender.
Sissalik was spared due to his bravery, but found himself once again in bondage, forced into the role of the new captain of Nanda's Luck under Yopayomba's authority. Her scheme involved using the ship, loaded with explosives, to crash into the terminal port of Quantill City harbor during the Portage Moon Festival celebrations. Yopayomba's intention was to ignite a planetary civil war among the Aqualish races, which would ultimately benefit the Galactic Empire. In exchange for her assistance in the plot, she was promised complete dominion over Ando's oceans.
However, Sissalik seized control of the Nanda's Luck and instead steered it into Yopayomba's flagship, the Majestic. This act ignited the Battle of Portage Moon and transformed Sissalik into a beloved folk hero on Ando.