S1·E16 The Cowbell of Happiness

Nanami holds a party to show off her designer's brand pendant. However, Juri shows up with a more gourgeous pendant. Luckily for Nanami, a packet comes for Nanami and according to Juri and Miki, the designer's brand is the top class. Nanami decides to wear it. However, the thing appears to be just a cowbell. Not knowing what a cowbell is for, from then on, Nanami is always wearing it and showing it off. Other people are aware of it, but can't bring themselves to tell her the truth. What's worse, Nanami is gradually turning into a cow because of the curse of the cowbell.