MOL is a short story written and drawn by Lynn Okamoto. It appears at the end of Elfen Lied Volume 1 as a special extra chapter, as well as in both publications of Flip-Flap. It does not take place within the Elfen Lied universe.
The unnamed protagonist, a college student who resembles a younger Kurama of Elfen Lied, shows no interest in dating girls. He flat out rejects a young woman's offer to go to the movies with him, much to the consternation of the crying woman's friends. They mock him as he leaves, saying he could be more tactful, that he looks like a doll with the blank face he always wears, and that his head must be messed up from "all the radioactive exposure."
The last girl's words are clarified by the protagonist as he narrates his life thus far. He lives in a small town that's home to a major drug manufacturer's research laboratory. For years, the research laboratory has been rumored to conduct cloning and human experimentation, and on top of the rumors, there have been damages done to local residences from the leakage of radioactive material. Because of that, the protagonist could rent an apartment right next to the lab for a very cheap price.
When he returns to his apartment after turning down the woman's date, he warmly greets the many dolls on display in his apartment. Some are adorable Raggedy-Ann style dolls, but most are smaller dolls, apparently ball-jointed ones. The dolls apparently all have names, as he greets a few of them by name and speaks to them as if they were people.
The protagonist details his life thus far, saying the traditions of his parents' families urged them to continue having children until they finally had a son. He is the youngest of nine children, with the other eight being all girls. As he puts it, "Any expectations you have about girls fly straight out the window when you live in a house with eight sisters." Due to his shrewish sisters treating him poorly, he has a distrust toward women, and he says it's because of them that he's obsessed with collecting female dolls.
He hears a noise from nearby, only to see a tiny woman, about the size of his dolls, trying to sneak out of sight. The naked woman apologizes and asks him not to be angry since she'll be leaving soon, but the protagonist takes her arrival as a gift from the heavens and asks her to marry him, much to her confusion. Rather than persist on that topic, though, he draws her a bath by putting hot water into a small saucer for her to bathe in since she's covered in dirt. The tiny woman notes it's the first time she's been in a bath and calls him a nice guy. He mumbles on that he must look like an ogling old man, but he's mumbling so she doesn't hear him clearly. After her bath, he gives her a set of clothes from his dolls, delighting her. He asks her her name, to which she replies "MOL 537," and when he asks what kind of name that is and where she comes from, she explains she's from a research laboratory. He concludes she means the lab next door, and she goes on to explain the horrid conditions of the laboratory. She was fed drugs and given injections, and she thinks they were testing to see how long it would take her to die. She explains there were others there, kids, who were put to sleep with drugs and others who had their bowels removed while they were still alive. The protagonist realizes she must be a guinea pig of the laboratory's experiments, and thinks back further to how he heard about them using small animals to test new drugs. He wonders if they've succeeded in making miniature versions of human beings, clone perhaps, to gain more accurate data during their experiments.
MOL 537 states her friends were all killed, one by one, and that the day before was supposed to be her turn. Instead, she escaped and made it into his apartment. He tells her she can stay as long as she likes, that he won't take her back to the lab, and while she thanks him, she says that's impossible. Her life will end in a week due to an injection the researchers gave her the previous day, and she says she just wants to see the world before she dies. MOL tells him she'll leave so she won't make him feel bad by dying in his house, and that the people looking for her would make life troublesome for him if they find out. She thanks him for the clothes and goes to leave, but he asks her where she thinks she can go since they'll surely find her and dispose of her quickly when they do. He again offers to let her stay there with him, and that he'll spend her limited time left with her.
The protagonist takes MOL 537 to school with him since he's in the middle of exams and can't skip class, and though it draws stares since he's holding her on his arm, he tells her not to worry since they'll just think she's a doll if she doesn't move. However, him talking to her doesn't go unnoticed, and the other students comment on how they thought he was weird before this incident but now see him as even stranger. In class, the professor asks him why he's brought a doll to class, to which he responds by bringing up the Compendium of Laws for Japan. In particular, he mentions the articles talking about the punishments for grave negligence, which would result in a fine of 1,500,00 yen or imprisonment of up to three years, which perturbs the professor. Making things worse, he lifts up MOL's skirt, and is promptly kicked out of class. The protagonist blames MOL, which angers her, but he defuses the oncoming argument by saying he's sick of exams and he'll put everything into the last semester, so they can go have fun instead.
While MOL is pleased, he takes her to the beach. While she's initially excited to see the ocean, she gets hit by a wave and asks if he's trying to kill her. He buys cheesecake for her to eat as well, but she eats too much of it and gets sick. He then takes her on a roller coaster, which results in her being even sicker. She yells at him for being mean and asks if he's trying to make her life shorter by riding such a thing. She then yells at a nearby zebra (presumably the two are in a park with rides and a petting zoo, or some such), saying it's the animal's fault that her friend insisted she ride on it, but the animal looks as confused as the audience must be at this point.
Come nightfall, the starlit sky and the city lights wow MOL, but she's exasperated by the protagonist never smiling the entire time they've been having fun. He answers that because of his upbringing, he doesn't know how to express his feelings, that it's just how he is, and he doesn't recall ever having laughed from the bottom of his heart or crying before. MOL calls it strange and goes on to say it's because he keeps playing with dolls all the time. Leaving the topic alone, she wishes she could have made him laugh at least once this week, which has flown by so fast. She asks him to leave cheesecake with blueberry syrup at her grave, though he only needs to do it once. She then tells him it's okay if he forgets about her, and tells him to be happy with a normal girl. He counters that by saying he'll be happy with her because she's a normal girl and asks why he has to forget about her. He tells her not to talk so foolishly, but rather than cheer up, she concludes that maybe she wasn't born a normal girl because she did something bad in a previous life. She confesses her love for him, asking what she's supposed to do. She wanted to swim in the sea with him the following year and to grow old together. MOL cries and says she shouldn't have run away because of how hard it is to die with so many wonderful memories and wishes. If they hadn't met, she wouldn't have such cruelly sweet memories. The protagonist consoles her by saying maybe she's wrong about dying during the week since she's so energetic and that he's sure she won't die. He asks her to be together with him forever, and, moved by this, she requests a kiss from him. He kisses her, but afterward, she asks for another one, which actually makes him laugh. MOL gasps in joy that she's finally seen him laugh.
Sometime later, the protagonist is approached at the school's rooftop by the woman with pigtails from the beginning of the story. She notices he hasn't been carrying his doll around with him anymore, then smiles and says "She was so cute...I really liked her, you know." The protagonist falls to his knees and grips the railing as he breaks down into tears, surprising the woman and bringing her to tears too.
The story ends with a parting shot of a tree with a slice of blueberry cheesecake sitting in front of it.
- "MOL" shares several similarities with Elfen Lied and can even be considered a prototype for both it and Brynhildr in the Darkness. Both stories feature a naked young woman fleeing from a research laboratory and finding shelter with a young man, as well as themes of human experimentation. Brynhildr in the Darkness likewise shares this theme, though without the young woman being naked. The protagonist also takes MOL out to have fun and let her forget her sad life, much like Kouta did for Lucy when they were children. As mentioned before, the unnamed protagonist resembles Kurama during the flashback of his younger years, and his wardrobe is the same as Kouta's. MOL 537's hairstyle is similar to Nyuu's as well, but closer resembles Kisaragi or Naru Narusegawa of Love Hina.
- Based on the classroom scene, the protagonist appears to be studying in law, perhaps criminal justice.