Ancient Egyptian statue moves on its own

The statue of Neb-Senu, believed to date to 1800 B.C., is housed in the Manchester Museum in England — at least for now. But if the statue keeps moving, there's no telling where it will end up.

The museum says it installed a stop-motion camera after reports the carving had started changing position, despite apparently not being moved by human hands for 80 years.

Oddly, the statue turns 180 degrees to face backward, then turns no more. This led some observers to wonder if the statue moves to show visitors the inscription on its back, which asks for sacrificial offerings "consisting of bread, beer, oxen and fowl."

What do you think is a plausible explanation? An ancient Egyptian curse? The vibrations of visitor footsteps? Or a train or trolley that passes by?