The Dodongo Snakes are a Mini-Boss in Link's Awakening. They always appear in a pair, wandering around the room in random patterns. Like regular Dodongos, their body is protected by a strong outer shell which cannot be pierced by Link's sword. The only way to defeat them is by feeding them Bombs.
The first encounter with the Dodongo Snakes is in Key Cavern, the third dungeon in the game. They are found near the north on the first floor in a separate room. When Link enters, the door closes behind him, but a staircase in the bottom left of the area allows him to escape if he needs more bombs. The only way to open the door into the next room is to kill both Dodongo Snakes. He can place bombs in their path so that they swallow them, or he can throw them into their mouths. Three bombs will kill one Dodongo Snake. After each one is defeated, they turn into Fairies. Once both are gone, a portal will appear that leads back to the entrance to the dungeon, and the door will open, which leads to the Pegasus Boots.
In Face Shrine, the Dodongo Snakes are in the eastern portion of the dungeon. They inhabit a room filled with pits that Link can fall into. Once again, the doors close upon entrance, but a northeastern staircase can be reached by jumping over a pit with Roc's Feather and then climbing up to exit the room. Nothing else has changed with the battle; again, the Dodongo Snakes can only be defeated if they ingest three bombs each. After they are slain, the door to the west opens, which leads to a room with a pit that Link can use the Hookshot to get over. After unlocking the key block on the other side, Link can walk to a room that contains the Nightmare Key.
The Dodongo Snakes are fought for the final time in Turtle Rock, along with many of the other Link's Awakening Mini-Bosses. However, this time they have to be killed in a specific way. Unlike previous encounters, the doors to the room do not close when Link enters. The room also has a ledge at the north; the Dodongo Snakes inhabit the lower part of the room. If they are killed in the lower part, the Treasure Chest appears on the top level and cannot be reached. If the chest is not opened, then the Dodongo Snakes will reappear again. Link must find the back exit from the dungeon that leads into the Tal Tal Mountain Range in order to reach the upper ledge of the room. Bombs can then be thrown down from the ledge to kill both Dodongo Snakes. After that, the treasure chest appears again, and Link can open it to find a Small Key.