WARNING! MINOR SPOILERS AHEAD! DO NOT READ IF YOU WANT TO GET THROUGH THE GAME WITHOUT ANY HELP OF ANY SORT!That being said, there are actually five frogs in the game, and they all need to be retrieved using the Don Gero's Mask, at which point they will give you a Piece of Heart. This means that there are two different Gekkos, and each one turns into a different frog. If this spoiled something for anybody, keep in mind I gave you fair warning in bolded caps above AND reduced the size of this text so you couldn't read it unless you tried.