The Selfish Child's Disappearance is the 38th episode of the Katekyo Hitman Reborn! anime series.
Under Reborn's instructions, Tsuna embarks on a search to find the missing Lambo. At the same time, Haru is testing Tsuna to find out whether he is still the kind and compassionate Tsuna who had saved her in the river because she thought she saw him harassing Lambo. Her first test is leaving a coin on the ground for Tsuna to find. He doesn't believe it and comments on how lucky he is. He uses it to buy drinks. Haru, Bianchi, and Reborn have different opinions. Test failed. The next test is Haru dressing up as a old lady. She is wearing a paper machie mask. When Tsuna walks up to her, she askes for directions. Suddenly, Haru's mask melts, and Tsuna runs away, frightened. Haru, Bianchi, and Reborn are shocked, (supposably) unaware of the melting mask.