Gnarled Root Dungeon is the first dungeon in The Legend of Zelda: Oracle of Seasons. The dungeon lies in North Horon, in the land of Holodrum. It requires the Gnarled Key to enter. Link obtains the Gnarled Key from the Maku Tree when he asks Link to save the Oracle of Seasons, Din. It bears a striking resemblance to Level 1 in The Legend of Zelda. Aside from being in a tree on an island with an bridge on the east, both are in the shape of a bird, have Goriyas as mini-bosses, and have Aquamentus as a boss. In addition, the floor layout is exactly the same; the dungeon item is even found in the same spot. However, the puzzles in the dungeon have been drastically changed, and many of the rooms are connected in different ways, like mine carts.
The Gnarled Root Dungeon is located inside a dead tree, which appears to be a mass of roots until Link uses the Gnarled Root Key. The tree is located on a lake in North Horon, very close to Eyeglass Lake.
As it is the first dungeon in the game, Gnarled Root Dungeon features few advanced puzzles. It contains a few walls that can be blown up, mine carts, an Old Man, and one simple side-scrolling area. Interestingly, the item found in the dungeon, the Seed Satchel, is of no use against the boss. Unlike many dungeons, this dungeon contains no pots; instead, bushes can be found throughout the dungeon. This makes sense, since pots would be of no use until the player received the Power Bracelet or the Noble Sword.
In Norse mythology, a dragon named Níðhöggr lives under the tree Yggdrasil and eats its roots, while an eagle lives on top of the tree. Similar to Level 1 from The Legend of Zelda, nicknamed the Eagle, the Gnarled Root Dungeon's shape resembles that of an eagle and its boss is a dragon. There may be a connection to this myth due to the dungeon entrance being a tree, its name revolving around the idea of roots, its interior being shaped like that of an eagle, and its boss being a dragon.