Tanna leaves were used along with the Scroll of Thoth to summon Anubis.
The Emir referred to the tanna leaves as “sacred.” Their location is unknown but Coyote had to leave the Sphinx to get them. The leaves gave Hyena hay fever.
Michael Reaves had wanted to use the tanna leaves in the Batman: The Animated Series episode, “Avatar", which he also wrote. 
Tanna leaves are fictional and are a reference to the 1940 film, The Mummy’s Hand.