The Legend of Zelda: Ocarina of TimeEdit
In the first dungeon Inside the Deku Tree while Link is a Kid Link finds the Slingshot while exploring the Dungeon. Later he can get two upgrades for its seed bag which allow it to hold 50 Deku Seeds. The first is a bee hive like target inside the Lost Woods and the other is at the Bizarre in Hyrule Castle Town Market.
The Legend of Zelda: Four Swords AdventureEdit
Link can find a slingshot on pedestals around Hyrule and use it as his weapon. The slingshot can be held down to shoot farther. the upgrade to it lets Link shoot three Deku seeds when he fires his Slingshot at full power.