The shadoks looked like birds. They had beaks and long legs, but their wings where ridiculously tiny.
In the beginning the Shadoks laid normal eggs. But because of their long legs, the eggs kept breaking. Therefore the Shadoks started laying iron eggs.
There are 2 types of eggs. Eggs with legs on the bottom and eggs with legs on the top. Those eggs were sent to the other side of the planet.
On the whole, the Shadoks were pretty evil creatures
So the Shadoks wanted to move to Earth. Unfortunately, all their efforts to get there on their tiny wings didn't go too well.