You have to have the egg with you and walk several thousand steps.
You don't see it. You have to hatch it from the Egg you received from Riley on Iron Mountain.
The coolest Pokemon in diamond would be Lucario, a fighting and sttel type Pokemon. To get one, you have to help Riley on Iron Island and he will give you a riolu egg. Hatch it and evolve it (by happiness) to get a Lucario.
on iron island you will meet a guy called Riley help him beat all the team galactic grunts and he will give you an egg from which riolu will hatch from
you run around sinnoh and it will hatch.
get a magcargo and put next to the egg in ur Pokemon thing
run around
Yes
You have to walk around with it. It will hatch faster if you have a Pokemon with the ability Flame Body.
you can't hatch a pikachu egg on diamond, it hatches in to a pichu.
you walk around for ages and ages and it will eventually hatch
The egg given to you by the hiker has a happiny and the egg given to you by riley has a riolu
I don't think there is!