A slaughter took place in 67 BBY on the transport Woebegone, when Darth Plagueis murdered the ship's personnel. This began with Plagueis secretly boarding the vessel. Upon interaction with the crew, he expressed his desire for secrecy and requested discreet transport to Muunilinst. Following deliberation, the crew opted to exit hyperspace and contact authorities via comm. Plagueis then used his lightsaber to kill Ellin Lah and after that he killed the rest of the crew. Subsequently, Plagueis arranged for the ship's destruction at the Deep Space Demolition and Removal, a Black Sun station, to conceal the events.
The two Sith Lords Darth Tenebrous and his student Darth Plagueis journeyed to Bal'demnic intending to create a weapon using a large amount of cortosis ore. Subtext Mining members, who had given Tenebrous a mining survey of the heated crystalline caves containing the ore, also supplied the Bith Sith Master with M-2 Mining Droids to extract the ore. Unbeknownst to Tenebrous and Plagueis, the mining droids were secretly programmed to ignite the caverns using pockets of lethane gas that were not mentioned in the survey report. Unable to stop the droids from releasing the highly flammable lethane, Tenebrous and Plagueis focused on escaping the cave and the resulting explosion. The two Sith Lords managed to head towards the grotto where their ship was located. While Tenebrous was focused on protecting the ship from the explosion, Plagueis took the opportunity to eliminate his Master by using the Force to crush the Bith under large stone slabs and rocks, and in turn, severely damage the very starship the two Sith Lords used for their arrival.
Even though Plagueis survived the explosion and successfully killed Tenebrous, he was stuck on Bal'demnic. Furthermore, in his effort to kill Tenebrous, Plagueis sustained back injuries from falling debris, resulting in a constantly bleeding wound that would become infected over time. The Muun spent the following evening reaching the Kon'meas Spaceport. Despite being hungry, lacking proper rest, and needing medical attention for his injuries, Plagueis was determined to ensure that no one would learn of his presence on Bal'demnic.
Eventually, Plagueis arrived at the spaceport. After searching for a long time, he discovered through his comlink that a structurally long freighter, with a registered model number of LS-447-3, was scheduled to depart for Ithor, which was close to his home planet of Muunilist. The ship, named “Woebegone”, was boarded secretly by Plagueis, who used the ship's cargo as cover. He hid himself inside one of the ship's refrigerated cargo bays, using his three hearts to regulate his blood to combat the low temperatures.
During the jump to hyperspace, the crew discovered Plagueis' presence on the ship. Led by Captain Ellin Lah, most of the Woebegone crew confronted the Muun, who had spoiled some of their cargo of aquatic organisms, with most of them coated in the Sith Lord's blood because of his untreated injuries.
As tensions rose between Plagueis and most of the ship's crew members, with the latter outraged that some of their cargo was ruined as well as the Muun refusing to share any details on his identity and why he did not leave Bal'demnic using the same ship he arrived in, Plagueis chose to negotiate privately with Captain Lah. Plaguies still refused to reveal his identity and his purpose on Bal'demnic, however, he did offer the crew reimbursement for their spoiled cargo as well as additional compensation for a safe passage towards Muunilist. Considering the Muun's offer, the Torguta Captain chose to talk with her shipmates to make a final decision.
Fearing that the Muun may have been involved in illegal activities on Bal'demnic, the crew decided to contact the authorities on Bal'demnic to find out if Plagueis was wanted in their sector before taking him to Ithor. When Plagueis learned from Captain Lah of the crew's decision, his warnings for her and the other crew members to reconsider their choice were ignored and Captain Lah had primed her blaster, for firing. Furthermore, the Woebegone had already stopped its route to Ithor by dropping out of hyperspace. Trapped, the Muun decided to act. Equipping himself with his lightsaber, Plagueis fatally struck the Torguta Captain, nearly decapitating her, before heading to the ship's cabin space where most of the remaining crew were present. When confronted by the now-hostile Muun, the crew immediately armed themselves with their respective blasters.
Unaware of the Muun's identity as a Dark Lord of the Sith, the crew was significantly outmatched. Plaguies had tossed his lightsaber into a spinning arc to maim crew members Semasalli and Blir', all but removing the former's left shoulder while removing the latter's antenna palps and scalp. The Klatooinian Wandau tried to finish the Sith Lord by firing his blaster at close range before Plagueis' still-spinning lightsaber returned to him, but Plagueis deflected his blaster fire and retaliated with Force Lightning, paralyzing the Klatooinian from the waist down. The crew's male Zabraak Maa Kaap moved in on Plagueis with a virbroblade and a series of melees after his own blaster was depleted. Plagueis avoided Maa Kaap's physical attacks and delivered a forceful kick to the Zabrak's thorax which sent him flying across the cabin space, causing Maa Kaap's spine to snap and his arteries to burst. The remaining crew members, Doo Zuto and PePe Rossh, however, managed to physically attack the Muun with teeth and claws after securing a hold on the Sith Lord, but Plagueis was unaffected. Plagueis ended the conflict by removing Pepe Rosh's face and Doo Zuto's snout.
After the onslaught, Plagueis attempted to preserve and study the crew members' midi-chlorians, but to his dismay, was unsuccessful as some of the crew members had died fairly quickly. Wandau, who was fully conscious, had mistakenly accused Plagueis for a rogue Jedi who could have used the force to compel the crew instead of killing them as the Klatooinian had apparently experienced this beforehand. Disgusted by what he perceived as a weak-willed Klatooinian, Plagueis killed him with the Force.
With the Woebegone crew all but neutralized, the ship's multi-function droid 11-4D, who acted as medical personnel aboard the ship, immediately came into the service of Darth Plagueis. The droid treated the Sith Lord's injuries, provided him with food and drink, as well as piloted the ship based on the Muun's coordinates to arrive at the Deep Space Demolition and Removal, which was operated by Plagueis' then business partner, Boss Cabra. With the Woebegone crew members either dead or comatose, Plagueis ordered the freighter to be sealed and destroyed aboard the Deep Space Demolition, effectively eliminating any witnesses of his presence on Bal'demnic save for the droid, 11-4D, who would continue to serve Plagueis for decades until the Muun's death at the hands of his apprentice.