Sarcophagus

Sarcophagus is located inside Boss room in pyramid, or inside Giraffi structure.

To open sarcophagus you must summon and defeat Pharaoh.

When defeated you can loot Sarcophagus. In Sarcophagus you find at least one artifact, based on Pharaoh type. Now you can mine Sarcophagus to get it and use like a cool chest.