In what could be the plot of the next summer blockbuster, a sealed sarcophagus has been found 16 feet underground in the Egyptian city of Alexandria, Science Alert reports. It’s still unknown who or what might be lying inside the nondescript black granite casket, but what’s clear is that it hasn’t been opened since it was closed more than 2000 years ago.

Ayman Ashmawy, head of the government’s Ancient Egyptian Antiquities Sector, observed “a layer of mortar between the lid and the body of the sarcophagus,” indicating it hadn't been opened, according to a Ministry of Antiquities Facebook post. Considering that many ancient tombs in Egypt have been looted over the years, an untouched sarcophagus is quite a rare find.

The sarcophagus was discovered when a site in the Sidi Gaber district, dating back to the Ptolemaic Dynasty (305-30 BCE), was inspected before construction of a building began. The casket is 104.3 inches long and 65 inches wide, making it the largest of its kind ever discovered in Alexandria. In addition, an alabaster statue of a man’s head was found in the same tomb, and some have speculated that it might depict whoever is sealed inside the sarcophagus. Live Science suggested that archaeologists may opt to inspect its contents using X-rays or computed tomography scans to prevent damage to the artifact.

Although it remains a mystery for now, Twitter has a few theories about who might be lying inside:

[h/t Science Alert]