Fringe of the Forest
The first room of this mossy dungeon is small, but packed with Green ChuChus. There are roughly a dozen in this one small room. Although you could use your Spin Attack to take them out, the Deku Leaf does a good job of revealing their heads so you can attack them. Just stand in place and fan it at them to stun them. If you check out the ramp on the right side of the room, you can open the treasure chest and pull out the Dungeon Map. You'll also notice the first of the series of Warp Jars is positioned next to the door in this room, which is protected by some weird eye-plant growth. In order to move through that door, you'll have to do something about the growth. Lucky for you, there's a Boko Nut growing on the left side of the room. Pluck it and toss it right in the eye of that plant thing (you've got to do this without getting too close, otherwise it'll shield itself) and the door will be ready to use.