When Gold Roger and his crew were sailing across the One Piece world, they kept a mysterious object aboard their ship. Every time the Oro Jackson was shown, it would have an enormous egg with polka dots on it. With the disbandment of the Roger Pirates, the fate of both their ship and this egg is unknown.
There is, however, a chance that the Egg was left on the New World's final island, Laugh Tale. If that is the case, it could give the Straw Hat Pirates -- and whoever else makes it to Laugh Tale -- yet another matter to deal with before they find One Piece. Whatever was in that egg could be waiting patiently for the right people to show up and claim Gold Roger's treasure.
Where Could Gold Roger's Egg Be Now?
When Roger was about to be executed, he claimed that he had left all of his spoils gathered in one place. In addition to the legendary One Piece, this would likely include all the treasures and valuables he collected throughout his life, among which the egg could certainly be counted. It also stands to reason that the egg has hatched by now -- after all, it was last seen over 24 years ago before Roger was executed. Whatever type of creature is contained within, it has had plenty of time to break out of its shell and grow to maturity.
A lot of fans have theorized that the egg contains a dragon. It may be a creature of myth in the modern One Piece world, but if a specimen still existed, the Roger Pirates, who learned all the secrets of the New World, would no doubt be the ones to find it. As for theories involving the dragons' relationship to the Ancient Weapons, that remains to be seen.
It should be noted that Roger's egg is unlikely to be directly connected to the One Piece. Roger didn't find out the nature of Joy Boy's legacy until his crew arrived on the then-unnamed island, by which point the egg was already aboard the Oro Jackson. He may have realized that his crew arrived too early, but that would imply he thought hatching the egg was an unrelated matter and probably wasn't counting on the egg's involvement.
In any case, if the egg did hatch into a dragon, then it would make even more sense for it to be on Laugh Tale. Dragons are well-known in mythology for being protective of hoards of treasure. Even if it's not intentionally guarding One Piece, it could very well be guarding the rest of the treasure Roger left on the island.
What Will Happen When the Straw Hat Pirates Find Roger's Egg?
If the egg is on Laugh Tale, the locals of the island are probably familiar with it. The Straw Hats might end up in a slight altercation with them, but it would be the main antagonists of the arc who seriously threaten the egg's safety. The Straw Hats would become responsible for stopping these villains and, in doing so, become friends with the monster. Whether such a subplot exists to pack an emotional punch or directly relates to the One Piece, Oda will no doubt use the significance of the egg to drive the point home.
Whenever that egg shows up again, it will likely have a major impact on the story. Whether the Straw Hats find eggshells aboard the Oro Jackson docked outside of Laugh Tale or the intact egg somewhere else, it will play a big part in their search for the rest of Roger's legacy. The closer they get to the final island, the more important that egg will have to be when it finally shows up.