This is an emu egg. One emu egg weighs about two pounds, or the equivalent of roughly 12 chicken eggs. Size, however, isn’t the only trait that sets emu eggs apart. Their stunning, emerald color makes them one of the most striking eggs on the planet. The blue-green hue is for camouflage. Emus lay their eggs in the grass and the color keeps them hidden from other animals. (Source)
That is a dragon egg
DRAGONS