A oneshot by NisiOisin and Miyokawa Masaru:
Sunaki is a back-up player on the baseball team. One day, he finally gets the courage to put a love letter into the school idol's shoe locker, but where will his actions take him?
(The title is a play on words: 変身願望! (Henshin Ganbou!), or Desire for Change!, vs 返信願望! (Henshin Ganbou!), or Desire for a Reply!)