Pokémon Sapphire Tips

Steven's Gift
After you defeat the Elite four, you will fight Steven, the champion. After you beat him, you are the new champion. Then, go to his house in Mossdeep. You will see an item on the desk. It is a pokeball containing a Beldum(steel, Level 5)
It knows take-down, and will evolve into a metang at level 20(steel, psychic). Sometime around level 45 it will evolve into a Metagross,(steel, psychic), Steven's most powerful pokemon!