Pocket Egg
The Pocket Egg is the first item in Ocarina of Time trading sequence, which grants you the Biggoron's Sword in the end. Link can start the quest as soon as he becomes an adult. To obtain the Pocket Egg, Link must go and speak with the Cucco Lady in Kakariko Village. She will tell Link that she has bred a new type of miniature Cucco that does not give her goose bumps. She will also comment on Cuccos loving to wake up lazy sleepers. She will then give Link the Pocket Egg, asking him to make the Cucco that will emerge from it happy[1]. In order to continue with the quest, Link must either wait in an area where time goes on normally (such as Hyrule Field or the Death Mountain Trail), or play the Sun's Song a couple of times. The Pocket Egg will then hatch and become a Pocket Cucco.