Malfunction is the 41st chapter of Akira Amano's Katekyō Hitman Reborn!.
Synopsis
While returning a book to the library, Tsuna meets up with Kyoko's best friend, Hana Kurokawa. She saw Tsuna together with Haru the previous day and uses this to blackmail Tsuna in order to see Adult Lambo.
Forced to comply, Tsuna brings her to his house where they are welcomed by Reborn, Lambo and I-Pin. Upon seeing Lambo, Hana tries to get him away from her since she can't handle kids. Just then, Haru arrives with some of her old clothes for I-Pin. After introducing herself to Haru, Hana tells Tsuna that she'll keep quiet as long as she meets the hot guy. Lambo then teases Hana calling her the Shoo Shoo Hag, causing Hana to attack him. A crying Lambo uses the Ten Year Bazooka on himself but ends up swapping only the bodies of him and his future-self, since the Bazooka malfunctioned.
Hana blushes after seeing him while Tsuna and Haru expresses their confusion. Adult Lambo then acts just like his younger self, much to everyone's surprise. As the bizarre event continues, Tsuna and Haru become scare of the Adult Lambo while Hana continues to admire him. When she tries to introduce herself, Lambo begins to call her Shoo Shoo Hag again. However, Hana sees this as something funny. When Lambo sees Haru, he begins to go after her asking her to play with him. Tsuna tries to ask Reborn for help, but he ignores him. Seeing Reborn, Lambo remembers his assassination mission and tries to attack him. However, Reborn shoots him with the Dying Will Bullet on left side of his head and leaves. The bullet causes Lambo's hair to grow in size which begins to suffocate Tsuna, Hana and Haru. However, he suddenly changed back to his younger self, but his mind seems to belong to the Adult Lambo. Thinking that Hana would like him now, Tsuna is surprised to see that she's getting Lambo to get away from her again which causes him to cry. The effects of the malfunctioned bazooka, causes Lambo to not be able to return to normal for a week...
Characters
Note: Bold + Italicized = First Appearance