A short story included at the end of Black Paradox.
Tsuyoshi is walking to his fiancee Miku's house when a mysterious woman attacks him and licks his face and hand. He falls ill and collapses and dies, as does Miku's dog, which had licked the woman's saliva off of Tsuyoshi's skin. Tests reveal a biotoxin in their blood. Soon afterwards, another man is killed by the woman, who has an enormous, elongated, infected tongue. People are warned to stay vigilant.
Miku is present on the scene when the woman is caught by the Neighborhood Watch as she attacks a child. Miku screams that she won't forgive the woman, and manages to bodily subdue her despite being licked. Miku survives because she washes it off right away; but is psychologically scarred by the incident. The woman is arrested and sent to a mental asylum, with no traces of the toxin found in her tongue or body. Many people who survived the woman's attacks are left with post-traumatic stress disorder and can't kiss their spouses or be licked by their pets.
Many years later, Miku is in a bar and meets a woman called Nagaoka. They get talking and discover they were both victims of the licking woman. Nagaoka tells Miku that the woman was recently released from custody, but she instantly disappeared and the authorities are worried. Miku vows that she must kill the woman in order to protect others. Nagaoka suggests that Miku cover her skin in deadly potassium cyanide, which Nagaoka can obtain from the laboratory where she works; and get the woman to lick it, thus fatally poisoning herself.
The woman soon begins to attack others, and kills five people. Miku tracks her down. When the woman licks the cyanide, she collapses and dies, but before she dies manages to reach into her mouth and physically rip out her own tongue. It dives into Miku's throat and almost chokes her, then falls to the ground. Miku watches a news report on the woman's death and is anxious that the press are not mentioning the whereabouts of the tongue.
Miku tries to call Nagaoka but the number is out of service. She also discovers that Nagaoka had lied about working at a laboratory. Miku realizes that the glasses in the woman's handbag looked a lot like those Nagaoka wore. She becomes paranoid, convinced that the whole thing was a set-up to further the woman's own ends.
Miku eventually begins a romance with a new boyfriend and starts to put her past behind her. But when they kiss, they are attacked by the woman's giant tongue and are found dead, poisoned by the potassium cyanide. Police ignore eyewitness reports of a giant tongue bouncing around at the scene.