Vaatrik Pallra is the main antagonist of the Star Trek: Deep Space Nine episode "Necessary Evil".
She was portrayed by Katherine Moffat.
Pallra was resident on Deep Space 9, then known as Terok Nor, during the Cardassian occupation of Bajor, with her husband running the chemist's shop. She first met Odo when he was investigating her husband's murder. She identified Kira Nerys as a suspect, claiming she was Vaatrik's mistress. Pallra had actually got the correct culprit but given the wrong reason: Vaatrik was the head of Gul Dukat's network of Bajoran collaborators.
Years later, Pallra had fallen on hard times so planned to make use of her history. She summoned Quark to her home on Bajor and employed him to retrieve a strong box hidden at the site of the old shop, not telling him it contained the details of Vaatrik's contacts. Suspecting Quark wouldn't be able to resist looking at the contents of the box, Pallra also sent a hitman, Trazko, to kill Quark and take the list.
Pallra succeeded in getting hold of the list and contacted everyone on it, blackmailing them into giving her 100,000 lita in return for her keeping quiet about them working for the Cardassians. When Odo visited her, she learned for the first time that Quark had survived and was in a coma, also learned that Odo was close to identifying one of her blackmail victims, Ches'saro. She had Ches'saro killed and sent Trazko to finish off Quark. He again failed and was arrested, with communication and bank records quickly connecting him to Pallra, who was also brought to the station under arrest. Pallra told Odo that she didn't kill her husband: Having already realised the truth, Odo simply said that he knew.
Pallra's name comes from the script. The episode simply refers to her as Mrs Vaatrik.