Ursula is based on the sea witch from the original fairy tale. However, while the original sea witch was an overall neutral character and played a small role in the story, Ursula was portrayed as evil and had an extended role in the film.
Ursula has the upper body of a pale blueish purple obese female human, while her lower half is that of a black and purple octopus.
The Little MermaidEdit
Ursula first appears watching Ariel and Flounder swim back to the palace using a magic globe. Having a grudge against Ariel's father Triton due to him banishing her from the kingdom, she orders her minions Flotsam and Jetsam to follow the young princess in the hopes of discovering a way to take revenge on Triton. Soon enough, she learns Ariel has fallen in love with a human prince named Eric, which she uses as an opportunity of vengeance.
After Triton destroys Ariel's grotto, Flotsam and Jetsam lure the depressed princess to Ursula's lair, where she makes a deal with her: she will transform her into a human for three days, and if she gets a kiss of true love from Eric, she will remain human forever, which Ariel agrees to. However, the consequence is that Ursula take her voice. However, Ursula sabotages Ariel's attempts to get Eric to kiss her, which culminates in Ursula transforming herself into a beautiful young woman named Vanessa, and she bewitches Eric into marrying her.
Scuttle discovers Vanessa's true persona, and warns Ariel. Right as "Vanessa" is about to marry Eric, Scuttle's enlists several animals to interrupt the wedding, and they smash the shell containing Ariel's voice, returning her voice and Eric's enchantment is broken. However, the sun sets on the third day before the two can kiss, returning Ariel to a mermaid. Ursula sheds her disguise and takes hold of Ariel and dives back into the sea. However, she is confronted by King Triton, who demands she return Ariel. Instead, Ursula proposes a deal to Triton that he take Ariel's place to save her, which Triton reluctantly agrees to.
Triton is transformed into a polyp, and Ursula takes his trident and crown. Ariel, angered, attempts to attack Ursula, who threatens to kill her. However, Eric intervenes and in the resulting confrontation, Flotsam and Jetsam are destroyed. Enraged, Ursula transforms into a giant version of herself and attacks the two, and conjures a whirlpool that raises a destroyed ship out of the sea. As Ursula attempts to kill Ariel, Eric takes control of the ship and drives it into Ursula's stomach. Ursula is then struck by lightning, which kills her. She sinks back into the sea, still impaled by the ship, while Eric gets to safety on the shore.