The second sphinx is the claim that a twin of the Great Sphinx once stood, or still lies buried, on the Giza Plateau. Its usual starting point is the Dream Stele, the granite slab Thutmose IV set between the Sphinx's paws around 1400 BC, whose carved scene shows two sphinx figures. In March 2026 the idea returned when Italian radar engineer Filippo Biondi said satellite radar data pointed to a second sphinx hidden beneath a large mound of compacted sand and rock on the plateau.

The theory is older than Biondi. In 2007 Egyptian researcher Bassam El Shammaa argued that the stele's doubled image pointed to a second, lost statue at Giza. When a rumor of a second sphinx destroyed in a storm circulated in 2017, former antiquities minister Zahi Hawass replied that the area "has been dug by so many archaeologists, and it yielded nothing." Biondi made his case on Matt Beall's Limitless podcast, saying he was about 80 percent confident and describing radar signatures of vertical shafts and horizontal passages like those he says lie under the Great Sphinx. The Daily Mail reported the claim on 26 March, and one post about it drew about 10 million views on X, according to Newsweek.

Archaeologists and fact-checkers rejected it. Newsweek rated the claim false on 27 March, noting that no excavation had taken place, no peer-reviewed study supported it, Egyptian authorities had announced no discovery and Egyptologists read the stele's paired figures as symbolism rather than a record of two statues. It added that ground-penetrating radar usually detects features only a few metres down. Radar specialist Lawrence Conyers, asked by AFP about the group's deep-radar method, said "it is impossible to reach such a depth with this technique," and Hawass had called the team's claims of columns beneath Khafre's pyramid fabrications. In August 2026 the journal Remote Sensing retracted Biondi and Corrado Malanga's 2022 radar study of the Great Pyramid, citing "serious methodological flaws and statistical errors."

The claim lived mainly in UAP and ancient-mysteries media, where fan accounts described Biondi as certain and tied his announcement to Chris Bledsoe's Regulus prophecy, which turns on the Sphinx's gaze. One account paired Bledsoe's remark that "two or three things" happening in Egypt that year "may change the history of humanity" with Biondi's announcement weeks later. No excavation has tested the mound, and the second sphinx remains, like the structures Biondi described beneath Khafre's pyramid, an unexcavated radar interpretation.