Glad Torpedo Ted
From the Super Mario Wiki
The G. Torpedo Ted (short for Glad Torpedo Ted) is a water-based enemy in the game Super Princess Peach. They are Torpedo Teds affected by Joy Vibes. Like all glad enemies, they have huge smiles and emit music notes and are also golden in color. While they're swimming forward, they move up and down, making them harder to avoid than their normal counterpart. As with all Torpedo Teds, they are invulnerable.