The 1989 version of the Little Mermaid might be better known as “The big whopper!” In the Disney version, the film ends with Ariel the mermaid being changed into a human so she can marry Eric. They marry in a wonderful wedding attended by humans and merpeople.
But, in the very first version by Hans Christian Andersen, the mermaid sees the Prince marry a princess and she despairs. She is offered a knife with which to stab the prince to death, but rather than do that she jumps into the sea and dies by turning to froth. Hans Christian Andersen modified the ending slightly to make it more pleasant. In his new ending, instead of dying when turned to froth, she becomes a “daughter of the air” waiting to go to heaven – so, frankly, she is still dead for all intents and purposes. (from Listverse)