Doukyo Suru Neneki - Season 1

Fujiwara Yuuji has had an unlucky life. As a child, he was falsely blamed for breaking a vase. He was fired from his job for a colleague's mistake. At the convenience store where he works part-time, Takamiya, a younger girl, blames him for errors made by others. When he returns home in a depressed mood, he is greeted by a strange girl. When Yuuji is puzzled, the girl reveals her true identity. She is a slime who has lived with him for the past three months. The creature, which speaks human language and can change its appearance, is in love with Yuuji. Yuuji is not at all pleased with the slime's affection. To attract Yuuji's attention, the slime changes her appearance into his coworker Takamiya and seduces him.