Uchu Chikyu

The one she truly fell in love with was Earth. A story about an alien who is self-conscious about her appearance.

An alien fell in love. The object of her affection was… “Earth.” To her, everything on Earth looks adorable. One day, a life form arrived from space with the intention of conquering Earth. To protect Earth, she must return to her true form and fight. If she stops being human in front of humans, they might find her repulsive. Even so, she will fight. For the sake of her beloved Earth, and for you, who are so cute—

(Source: Kadokawa, translated)

Note: Originally self-published on Twitter and Pixiv under the title "Watashitachi no Koto ga Suki na Kawaikunai Uchuujin no Hanashi (私たちのことが好きな可愛くない宇宙人の話)", was then licensed by Kadokawa for commercial release under the present title.