Scroll of Thoth
The Scroll of Thoth (with the assistance of Tanna Leaves) enabled a user to summon and imprison Anubis. It also contained a magical spell which allowed its reciter to become an avatar of the Jackal God, partly by invoking the power of the Egyptian gods Osiris, Isis and Set. The Emir used this scroll to become Anubis' avatar (although the first time that he attempted it, Jackal intervened to make himself the avatar instead). The Scroll of Thoth was presumably lost forever after the Emir sealed off the temple within the Sphinx where he had summoned Anubis. ("Grief")
Real World Background
Thoth was a god of learning in Egyptian mythology, who appeared like a man with the head of an ibis. The Greeks identified him with Hermes, whom they also viewed as a god of learning, of a sort.
The scroll bears some resemblance to the Book of Thoth, a legendary book of powerful magic spells said to have been buried with the Egyptian Prince Nekerkaptah.
The Scroll of Thoth is a plot device in the 1932 movie The Mummy, starring Boris Karloff. In that movie, it is the Scroll of Thoth that brings the mummy back to life.