Danse des petits cygnes is a famous dance from Tchaikovsky's Swan Lake, from the ballet's second act, the fourth movement of No. 13. Translated from French, it means "Dance of the Little Swans", also known as "Dance of the cygnets". It is very challenging because all dancers must look the same.
Lev Ivanov's choreography—created for the famous revival of Swan Lake in 1895—was meant to imitate the way cygnets huddle and move together for protection. Four dancers enter the stage in a line and move across with their arms crossed in front of one another, grasping the next dancers' hands. They move sideways, doing sixteen pas de chat. Ideally the dancers move in exact or near-exact unison. At the very end, they break their chain and try to "fly", only to drop to the ground.