Cymotes were purple and parasitic organisms that were believed to have died out millennia before the Galactic Civil War occurred. These creatures, considered a terrifying and horrific menace, implanted their eggs inside the mouth of a living being, with the hatched offspring then devouring their way out of the host. Despite having fragile bodies beneath their shells, they were considered palatable. The unconventional archaeologist Doctor Chelli Lona Aphra noted that they were a favored adornment for the tableware of the ancient Merelithic civilization. In the year 3 ABY, a number of cymotes, despite being thought to be extinct, were found on board the opulent cruiser Opal Empress as it ferried Ebann Drake to what he described to his relative Domina Tagge as a chance for an amazing deal.
Later, Tagge dispatched Aphra and the smuggler Sana Starros to find Drake and uncover the nature of this opportunity. However, by the time they reached the Opal Empress, the cymotes had slain all of the Opal Empress' passengers, including Drake. As they navigated the vessel, Aphra and Starros stumbled upon the lifeless bodies of the passengers, though they were unsure of the cause of death. The pair proceeded to a cabin to locate Drake, and Aphra detected sounds emanating from the vents, which unbeknownst to her were from the cymotes. Aphra inquired of Starros whether she had also heard the noises, but when she asked what Aphra had heard, the noises ceased. Eventually, they discovered Drake's remains and learned of his grand opportunity: an invitation to a Crimson Dawn sale where they intended to auction off the Han Solo. As Starros and Aphra discussed the auction, they were targeted by the bounty hunter Durge, who had arrived to collect a reward for Drake.
While Aphra and Starros conversed with Durge, the cymotes emerged from the vents and latched onto Durge, although he managed to dislodge them. The three then entered a room. Aphra recognized the creatures and informed Starros about the threat they posed. After Aphra mentioned that they were believed to be extinct, Durge declared he could rectify that. Starros inquired about the cymotes' vulnerabilities, and Aphra revealed their sensitivity to changes in air pressure. Upon hearing this, Starros suggested expelling them through an air lock, and they proceeded towards one. Durge enticed the cymotes into the air lock, but Aphra also ejected him into outer space along with the cymotes. The rapid decompression caused the cymotes to explode upon exposure to space.