The Sarcophagus of the Heretics puzzle is a relatively easy puzzle, with a complicated set up. It is located in the Tombs and Curses room, and acts as a hiding spot for part of the Ixupi vessel. It is located on the Egyptian side of the Tombs and Curses room.
The sphinx that tells what the cartouches should be.
The sarcophagus of the Heretics, the obelisks on each side.
The puzzle actually begins by approaching the Sphinx model, and pushing the button. It then makes an announcement involving the heretics, a pharaoh and his queen, who tried to convert Egypt to a single deity belief system. After hearing that, three panels on the obelisks must be rotated to match the cartouches of those figures. Since each obelisk has four sides, there are four options for each of the three parts of each cartouche. With six panels in total, and four options for each panel to start with, there is a 1 in 4096 chance of it starting in the solution. The correct solution can be found in the book, Egyptian Hieroglyphs Explained. Also, the correct patterns will match up, making it easier to find the solution.