That's a Bad Egg. It's not really a Pokemon egg, but rather, a glitch.
A Pokemon egg have no name, but when the egg hatches you can give the Pokemon a nickname.
A Pokemon egg cannot die ever.
to get a pokemon egg you must leave two compatible pokemon in the daycare center together. after awhile they will breed an egg
there is no jirachi egg trick, but there is a celebii egg trick in Pokemon crystal
I think a egg with a shiny Pokemon in it is a different color
i think the Pokemon that made the egg with ditto could have an HM move example:surf then it goes to the egg and the Pokemon that came from the egg knows that move.
Any Pokemon with a matching Egg Group can be able to breed. Ditto, with the exception of having its own Egg Group, can be able to breed with any Pokemon, except for Baby Pokemon, Legendary Pokemon (Besides Manaphy, who can be bred with Ditto to get a Phione Egg), and No-Egg grouped Pokemon.
Riolu is 4 generation Pokemon. You can get egg only in Pokemon Diamond and Pearl
Depends on what "the egg" is.
if you put a couple of Pokemon in the day care you Will get a egg by breading Pokemon
just put a male pokemon and a female pokemon that are in the same egg group in the pokemon day care west of striaton city. it will take some time for them to make an egg but the day care man will call out to you once the pokemon have made an egg
Egg groups indicate which Pokemon can breed with which. One Pokemon can be in several different egg groups, and some are in no egg groups at all because they cannot breed (legendary Pokemon, for example). If you want to breed your Pokemon, first look up what egg group(s) it is in, and then what other Pokemon are in the same group(s).