I will ki|| myself if no one answer this :( I know this is not about work but I need help. I was watching an anime years ago and I can't remember the name but I hope my description helps.

The anime is about a boy raised by a computer and has a monster friend who eats his arm to survive but the monster didn't mind. Then he turns into a mecha and a spaceship came to take him away... PLEASE tell me the name :(