The Little Mermaid was a 4-issue mini-series of comics published by Disney Comics late into its life cycle, based on the 1989film of the same name. Like the later Marvel Comics series and the TV series, they took place prior to the first film, with at least four issues being released. One of these issues, Serpent-Teen, elaborated on how Ursula got her lair.
Each issue had two cover variants; one of which is taken directly from a still from the film (specifically, issue 1 has Ariel singing the final verses of the "Part of Your World" reprise; issue 2 has Ursula in the immediate aftermath of transforming back from Vanessa; issue 3 has Triton and Sebastian talking; and issue 4 has Sebastian trying to talk Ariel out immediately prior to "Under the Sea.")
The "Serpent-Teen" arc, from the first two issues, was later reprinted as the 11th issue of the Cartoon Tales graphic novels, labeled as The Little Mermaid: Ariel & Sebastian, while "Clams Casino" from issue #4 was reprinted in Disney's Colossal Comics Collection #9. "Serpent-Teen", "Guppy Love", "Eric Meets Her Highness", and "The Hunt for the Redhead Down Under" were all eventually reprinted in Disney Princess Comics Treasury.