It was a ghost.
Jack was staring at the ghost frozen in horror.
The ghost started to speak and introduce herself.
She is a Queen and she has waited for help because she needs a book of the Dead.
She could go to the Next Life if she can find the book which was written magic spells.
She stated that the magic spells can help her to pass through the horrors of the Underworld.
The Underworld illustrated by her was so terrible.
Also, the ghost-queen mentioned that her brother hid the book and craved a secret message on the wall.
However, she could not see in proximity to things by her eyes.
Even though Jack lent his glasses to her, she could not wear that because she was a ghost made of air.
Jack could not speak continuously because he was so scared, but he is able to make his voice.
Jack stepped to the wall in order to construe the hieroglyphs and surprised.