Early 2000s sci-fi show, maybe late 1990s. A teenage boy and his friend, I think she was a black or Spanish girl. The boy ends up going to another planet or dimension. I think he was looking for his father.
The ruler of this world has the power to transform his arms and body parts into weapons.
The boy later on finds out he has the same abilities as well. I believe the boy and his friend were able to travel back and forth between Earth and the other place.