In Hans Christian Andersen’s “The Little Mermaid,” the mermaid becomes sea foam after the prince marries another woman.
The original 1837 tale differs sharply from Disney’s adaptations. Andersen’s mermaid gains human legs in exchange for her voice, but every step causes her pain, and the prince does not ultimately marry her. He marries a princess whom he believes rescued him from the shipwreck.
The mermaid is given a chance to survive by killing the prince with a knife, but she refuses to harm him. At sunrise, she throws herself into the sea and dissolves into sea foam. Andersen then adds a spiritual ending in which she becomes an “air spirit” and may earn an immortal soul through centuries of good deeds.
Disney’s 1989 film replaces this tragic ending with a romantic resolution. That difference is one of the most important distinctions between Andersen’s literary fairy tale and the animated movie.