Kurma - The Turtle
Lord Vishnu incarnates himself as
a turtle. It is an interesting story
involving both the Gods and
Demons.
The Gods approached Vishnu for
help. Vishnu then told them to
them to churn the Ocean of Milk
after adding medicines into the
ocean. He requested that the Gods
ask the Demons to help them in
the exchange of sharing the nectar
of immorality.
Both the Gods and Demons
churned the ocean, using the
serpent Vasuki as the rope.
But as churning was proceeding the mountain was sinking and then Lord Vishnu took the form of the turtle, named Kurma, and kept the mountain afloat. As soon as the nectar of immortality was out, the demons grabbed it.
Then Lord Vishnu took the form of a beautiful maiden, and seduced the asuras into letting her distribute the nectar. As soon as the devatas were served the maiden disappeared thus totally deceiving the demons and making them totally weak.
The video is a great depiction of the story, titled 'Dashavtar Illustrated Story - Kurma Avatar...The Turtle Incarnation'