The Little Mermaid S01E12 - Red

The Little Mermaid (1992)
S01E12 Red
Episode Overview
Following Ariel's party, King Triton begins to feel his age weighing on him. His luminous glowfish decides to help by giving him a magical age stone that transforms Triton into a young boy named Red. When Ariel and Sebastian uncover the truth behind Triton's transformation, they set off on a quest to track down the jewel's source, discovering that it leads to a powerful sorceress who can only be defeated by the true King Triton.