a togepi.
Riolu is 4 generation Pokemon. You can get egg only in Pokemon Diamond and Pearl
A Togepi hatches from the egg.
No
Depending on what Pokemon it changes
select the egg and say release
It depends on the egg.
Arceus awakens the Pokemon you Choose, Palkia, Dialga or Giratina. The egg hatches during the event, and that Pokemon joins your party. It is Lv. 1.
the mystery egg is a togepi...it hatches after walking with it for awhile
there's no egg in Yellow. there is in Gold and Silver but not the earlier versions.
the steps to hatch an egg depends on what Pokemon you have in the egg. it normally takes more steps for rarer Pokemon in the eggs. Good luck hatching eggs!!!!! ;)
you cant hatch a bad egg
How do you know when you get a bad egg is that it takes way to long to hatch.