Starfy

Starfy (スタフィー) (or "Prince Starfy") is a character who first appeared in one of the Mario games, Mario & Luigi: Superstar Saga.

Mario & Luigi: Superstar Saga
Starfy has a cameo appearance on a movie poster read "LEGEND OF STARFY". It is located in the Yoshi Theater.

Super Princess Peach
Starfy was created by TOSE and appears as an enemy called a "Starfish". It describes him, "A star-shaped foe rumored to be the prince of a kingdom". This describes a bit of Starfy while he was a prince.