The Mysterious Sphinx is an ivory and silver statue and represents a young woman. The face and shoulders in ivory are adorned with a helmet made of silver, which turns into a shoulder harness along the neck. The facial expression is serene, as is the pose of her hand, which she brings to her lips in an elegant gesture. This contrasts with the snake curling around her wrist, the helmet and the armour. The helmet is decorated with an eagle with spread wings and an open mouth, referring to war and victory. The armour is decorated with floral motifs, including poppies, from which opium is extracted, among other things. The combination of the beautiful and attractive on the one hand and the dangerous, narcotic and destructive on the other is also reflected in the image of the femme fatale.

Charles Van der Stappen (1843-1910) made it for the Colonial Exhibition in Tervueren (1897), using the ivory that was offered free of charge to Belgian artists for the occasion. The proceeds from the sale of their works also went to them. The aim was to promote the natural riches* of Congo, the Belgian colony - then still Congo Free State, which was the private property of King Leopold II - in order to provide critics with a rebuttal and to colour public opinion more favourably towards Leopold II's private domain (propaganda colonial policy by Leopold II). Van der Stappen submitted two works, of which the Sphinx was the least spectacular. When the Mysterious Sphinx was unpacked and set up, an option was immediately taken to purchase it for the future Africa Museum, which would become the megalomaniac permanent successor project to the colonial sections at the International Exhibition of 1897.
The Belgian state ordered a version in marble -without hand- for the Museum of Fine Arts, which Van der Stappen would deliver a year later.

Originally, the sculpture was on an onyx base, specially chosen by the artist because of a large amber spot, and stood on a Paul Hankar pedestal.

It is a relatively large sculpture, which was part of the spectacle of the ivory sculpture on display during the international exhibitions. The use of the ivory of the African elephant allowed this, as the animal (and thus the tusks) were considerably larger than those of the Asian elephant. The dimensions, the themes the sculptors were free to choose, and the style surprised the public. The works in ivory and precious metal on display were reminiscent of Greek antiquity, where cryselephantine (derived from the Greek words of gold and of ivory) sculpture had its first peak.