The sphinx is a mythological creature, resembling a human woman, with the haunches of a lion and wings of a bird and razor sharp teeth. She gives seemingly impossible riddles to people who come her way, but if they solve the riddle, she may just grant them what they want. Her head swivels and follows your Poptropican.
As part of the quest, you have to retrieve the rose from her garden. However when you reach there the flower is dead and she appears to be asleep. If you click on her she will wake up and challenge you to bring water back to the land. You will then have to solve the aquadect puzzle. The flower will then revive itself and you can pluck it. The Sphinx will then state that "Your fate awaits you", hinting that she knows what is going to happen after this.