Fukigen na Majo to Uchiki na Kedamono

Synopsis

He's in love with a witch? Subaru's in love with his senpai the selfish, eccentric, science geek, Tsukinowa Fubuki and therefore become her assistant. When she forces him to try her new experimental potion, he suddenly changes! With his new transformation, can he finally have the courage to confess to his beloved senpai?