From publisher blurb:
Paragons of Wisdom and Might!
The majestic sphinx is more than just a symbol of the ancient lands of the Nile. It is a symbol of power and wisdom, a guardian that stands throughout the ages. Sphinxes have a long history in fantasy roleplaying games, and several distinct breeds have shown up throughout the years, but Mythic Adventures provides only a single mythic sphinx to work with.
This book provides two more mythic sphinxes, each with several never-before-seen powers an abilities. The guardian sphinx, who takes its role as a guardian of important people and objects very seriously, and is magically able to shroud creatures and objects from detection—even if they’re buildings the size of mountains! It can also levy its powerful guardian’s riddle to foil would-be tomb raiders, who must answer correctly or be trapped in an extraplanar hell. Its roar is so mighty that it panics even the greatest of warriors, and saps the strength from those who hear it. And if all that fails, the guardian sphinx still has several other tricks up its sleeve.
The Nile sphinx is somewhat different: a colossal sphinx-shaped construct made of immense blocks of sandstone. It, too, employs a magical riddle that dooms those who are unable to answer it, but it also has power over time, halting it for the sake of itself and allies, or speeding it up to age foes into oblivion, among other dangerous abilities.
Finally, there is a brief discussion on handling riddles at the table, which provides some helpful guidelines for ways in which to use ability and skill checks to adjudicate such circumstances, and also provides several sample riddles.