Pirates of the Barracuda Galaxy.

A space pirate from the distant Barracuda galaxy, possessing amazing superpowers, comes to Earth. To escape the punishment of harsh cosmic law, the alien takes on the guise of a quiet schoolboy, Mitya, and begins searching for a repeater left on Earth in time immemorial to send a distress signal to his team. He accidentally saves the girl Kristina, who is being bullied by her classmates, and finds himself in the same company with the young hooligan and bully Kolya. Now their common task is not only to escape from their alien snake-people pursuers, but also to defuse a bomb that could destroy the entire solar system. But in order to save the Earth, you first have to understand that only friendship and self-sacrifice can resolve problems on a galactic scale.