With my reading of the real life Daring Do books, I can safely say that this poster is actually canon. In Daring Do and the Marked Thief of Marapore, there is a mystical artifact that is said to heal any ailment that is said to be in an underwater temple of Tehuti. Tehuti is an egyptian god of knowledge and wisdom. And what does she go anywhere but the egypt equivalent in the world of FiM.
There are possibly different ones with lion heads and pony heads.
Similar how the griffins in the show have different bird heads.