Ella Harper's Shoes

Origin
Ella Harper (5 January 1870 – 19 December 1921),[1] known as "The Camel Girl", was born with a very rare orthopedic condition that caused her knees to bend backwards, called congenital genu recurvatum. Her preference to walk on all fours resulted in her nickname "Camel Girl". In 1886 she was featured as the star in W. H. Harris’s Nickel Plate Circus, appearing in newspapers wherever the circus visited. The back of her pitch card reads:

I am called the camel girl because my knees turn backward. I can walk best on my hands and feet as you see me in the picture. I have traveled considerably in the show business for the past four years and now, this is 1886 and I intend to quit the show business and go to school and fit myself for another occupation.

Effects
When worn, the shoes will cause the user's knees to reverse their current direction without causing physical harm or pain. No matter the new position of the knees, the user will develop a preference to walking on all fours. When neutralized, the effects are harmlessly reverse.