Four-Legged Duck.

From the website:

Zhang Baoxiu, a farmer, shows an odd duck with 4 legs at Minzhu village in Zaozhuang city, east China's Shandong Province, July 7, 2006. Zhang Baoxiu bought a duck in June, 2006. The duck has four legs, two of 4 webbed feet are normal, and the others grow together. The duck can walk on land and swim in the water like other normal ducks.

Link - via Arbroath