The discussion revolves around identifying a rock that a user believes might be a nest or an egg. Initial suggestions point to the possibility of dinosaur eggs, but further analysis reveals that the rock likely contains fossilized bi-valve sea shells within a water-worn pebble. The context of the rock's location near St. John's, Arizona, and its proximity to the Petrified Forest National Park suggests it could be related to fossil reptile eggs, though the evidence does not convincingly support this. The conversation emphasizes the importance of context in rock identification, such as the geological history of the area and the characteristics of the specimens. Ultimately, while the rocks are intriguing, they may hold more value as a mystery than as definitive fossil evidence.