The Melancholy of Balalaika (バラライカの憂鬱 Bararaika no yūutsu) is the third Black Lagoon omake. It was originally released in the third manga volume on April 19, 2004, and it was later animated and released on the third Japanese Blu-ray disk on February 10, 2010.

At an elementary school, Dutch berates Balalaika for not raising Hänsel and Gretel well since the children were building pipe bombs in the second grade. As Balalaika thinks to herself about her lack of parenting skills, Hänsel and Gretel innocently sit still as Dutch claims that they burned all of the hair off a classmate's head. Nervously apologizing on their behalf, Balalaika then angrily orders the two to apologize as well, but the twins pout and make fun of the bullied kids. Annoyed by their unrepentant attitude, Balalaika smacks the kids, making them cry. After another incident, Roberta furiously berates Balalaika's parenting, causing her glasses to break as she speaks. The maid asks her if she is ready to take responsibility for Garcia's breakdown, but the embarrassed Balalaika claims that she does not know what she is talking about. Earlier, Hänsel and Gretel ask Garcia if he wants to play "doctor," showing him several surgical tools and cutting utensils. He tries to run away and says that he is missing his favorite anime, but Hänsel happily grabs him as he and Gretel tell him that they can play doctor the way adults do. Crouching in terror, Garcia cries out as Gretel tackles him, and Hänsel recommends playing "Unit 731."

Afterward, Garcia hides under his bed covers in fear and mumbles about the incident, much to Roberta's horror. Licking lollipops, Hänsel and Gretel insult Garcia as a wimp and blame him for not being able to handle the game. Yelling at her children, Balalaika orders them to apologize, commenting to herself that her anxiety continues to grow. At night, she tries to talk to her husband Chang, but he refuses to get involved and continues sleeping, asking her to deal with the matter since she is supposed to raise the children. Entering the twins' room, Balalaika is happy to see them sleeping peacefully until she discovers two caged, terrified kittens as well as books on murder and how to make a shamisen (which have hides made of cat fur). As the twins snore, Balalaika quietly takes the cats out of the room. The next morning, Hänsel and Gretel go to their mother in the kitchen and ask her if she has seen the pressure cooker. Tiredly thinking, she tells them that it is in the pantry, but she warns them that she will kill them if they use it with ball bearings, wiping the smiles off their faces. Continuing to wash dishes, Balalaika remarks that she has now gotten used to her parenting.