The Three-Year Smile of Death (微笑み三年殺し Hohoemi sannen-goroshi?) is the 366th chapter of the manga. It is also the first and only chapter of the Three-Year Smile of Death Arc. One afternoon Mousse invents something he calls a "Love Rocket" which he rushes to show to Shampoo. However trips and the rocket goes off in Shampoo's face. Mousse is terrified that Shampoo is going to beat him up, but she simply smiles and tells him that she's happy and goes back to her laundry. This convinces Mousse that Shampoo is using an Amazonian technique known as the "Three-Year Smile of Death" against him, which involves treating an opponent with kindness while torturing them through numerous "accidents" and minor attacks, all the while not appearing to be angry with them.