There is a Japan-only Nintendo game for the classic Gameboy called Kaeru no Tame Ni (translation: For the Sake of the Frog). The game centers around you, a young prince out to prove yourself against your rival in the big world. Along the way you get cursed and changed and turn into a frog. 

Now, it may interest you to know that your rival is a man named Prince Richard. In fact, it's the very same sprite for Prince Richard in Legend of Zelda: Link's Awakening (the prince who returns the Slime Key for his Golden Leaves). Additionally, the frogs in Richard's house in LA are the same sprites as the regular frogs in Kaeru no Tame Ni, and Richard's background music is a more upbeat version of the Kaeru no Tame Ni overworld theme. 

Kaeru no Tame Ni was released approximately two months before "Legend of Zelda: The Island Where One Dreams" (Link's Awakening) in Japan. A little more obscure than most of the references in the game ^_^;;