The Little Mermaid (1992)

S1E10 The Evil Manta

Atlantica is a beautiful city, but everything changes when Ariel accidentally frees a wicked manta ray from captivity. His malevolent influence ignites prejudice among the sea creatures, causing them to turn against one another. While the rest of Atlantica fractures into divisions, Ariel and Flounder remain united, determined to mend the rifts and restore harmony to their underwater home.