3 Revolution

One night, while the three Naruse brothers—Akito and his two younger siblings—are stargazing at a quiet shrine during a Leonid meteor shower, something strange happens. A mysterious alien creature named Piroshki appears from the sky. Intrigued and bewildered, the brothers bring Piroshki home with them. However, one of the alien's strange objects ends up in their possession.

(Source: Kadokawa, translated)