Sora x Lila: Sorairo no Lila to Okubyou na Boku
ソラ×リラ〜宙色のリラと臆病な僕〜
The story of the bitter-sweet romantic-comedy manga revolves around Shuu, a shy middle school boy who had an unrequited love toward his childhood friend, Sora. One day, she suddenly goes missing, but when she comes back, she's become an alien!
(Source: ANN)