Poacher's Saw
The Poacher's Saw is an item that is part of the Ocarina of Time trading sequence in The Legend of Zelda: Ocarina of Time. You get the poacher's saw from Grog in the Lost Woods and if you take it to a carpenter in Gerudo Valley he will give you a broken Biggoron's Sword which you can later fix to get a sword two times stronger then the Master Sword. You can only do this as an adult.