Biancheng Ke Xi Chushou Guai Hou, Tamen Geng Fengkuangle!

For unknown reasons, Xiao Zheng would transform into a tentacle monster when he became excited. Even if he longed for love, he would disguise himself as being cold. But suddenly he was summoned by Bai Anan, who was usually serious but secretly loved drawing. He signed an agreement and became Bai Ana...

Source: MyAnimeList