New answers tagged anime
Gantz, might be the anime you're talking about.
I wasn't able to find any "old" graphics anime. Was it Astro Boy?
Is it Iron Kid? It's not Japaneses but a South Korean-Spanish cartoon. It also has a dubbed version known as Eon Kid. He is a kid who got a robot arm which got stuck in his arm and gives him a full robot body. I don't know the whole story but he did fight with some government kind of organisation.
Ben 10? This is the only boy alien show I remember. The boy, named Ben finds an alien watch called the omnitrix which attaches to his wrist and allows him to turn into different aliens. He uses this alien technology to fight crime and other aliens.
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