When Joyce Byers and Jim Hopper entered the Upside Down to search for Will Byers, Hopper found an egg that was hollowed out and cracked open at the top and briefly studied it .
It is currently unknown if anything hatches out of these eggs.
Behind the scenes
Aaron Sims Creative created the concept art for the egg. The company Fractured FX, who made the prosthetics for Will's fake body and Barbara's corpse, created the prosthetic for the egg as it was seen in Chapter Eight.
Though it is not visible in the show, Aaron Sims revealed in an interview that the Monster was feeding off one of the eggs when Nancy saw it, even through she said that it was eating the Deer.