Dodongo

Dodongos are tough-skinned creatures typically resembling  dinosaurs. They have been depicted both as bosses and generic enemies. Defeating them generally involves feeding them bombs.

The Legend of Zelda
A Dodongo first appears as the boss of the second labyrinth, Moon, where an old man gives the vague hint that it "dislikes smoke." In later dungeons, they are found as generic enemies, often in groups of three. Trios of them also act as bosses in the Second Quest. To defeat them, Link can feed them two bombs directly, or stun them by having them in a bomb's blast radius, before finishing them off with the sword, rewarding him with four bombs. Dodongo is among the only bosses to not shoot projectiles, and is also the only boss capable of visibly changing direction. Despite looking like Triceratops, the English manual instead calls them rhinoceroses.

The Legend of Zelda: Link's Awakening
Highly abnormal-looking Dodongos appear in pairs as minibosses throughout the game, first appearing in Key Cavern. The Nintendo Power guide refers to them as Dodongo Snakes. They have no eyes or legs, large-lipped mouths taking up their entire fronts, and black bodies divided between a rounded head and a wholly-spherical body. When fed a bomb the sphere in back will briefly inflate, and in The Legend of Zelda: Link's Awakening DX, their blue details will briefly turn green. They will typically turn away if a bomb is placed in front of them, meaning placing the bombs must be timed well. After three bombs, each will explode, and leave behind a fairy. Unlike most minibosses, Link is not barred from leaving any of the areas featuring them, likely as the required item cannot be used infinitely.

According to Hyrule Historia artwork, the game's version of Dodongo was conceptualized as 「ドドンゴ ウナギ」 (Dodongo Unagi, or "Dodongo Eel").

The Legend of Zelda: Ocarina of Time
Dodongos are depicted as rare enemies, appearing in Dodongo's Cavern, having been placed there by Ganondorf after they had long been driven out. Here, they are bipeds, with green scales on their bodies and gray scales on their heads, a distinction that is made clearer in the 3DS version. Unlike previously, they are capable of breathing fire, specifically in long streams after deeply inhaling. Here, they can be defeated by placing bombs or Bomb Flowers in front of them at the exact right time, or by repeatedly attacking their tails. After each attack on the tail, they will rapidly spin around to hurt Link. After they get damaged enough, they will collapse and then violently explode.

Aside from the generic Dodongos, Baby Dodongos are shown, along with their leader, King Dodongo. A huge Dodongo skeleton makes up part of Dodongo's Cavern, with its skull concealing a passage in the main room. Crude cave artwork of Dodongos also appears in Goron City, appearing red in the original and green in the 3DS version.

The Legend of Zelda: Majora's Mask
Dodongos appear on the North side of Termina Field. In the daytime, two can be found underneath the stone mushroom-shaped platforms. One is roughly the same size as the ones in Ocarina of Time and gives a red Rupee upon defeat, but there is also a larger one that takes more hits and is more difficult to feed bombs. It gives a purple rupee upon defeat. Two large ones can be found in a grotto in the vicinity at any time, each giving purple rupees. Defeating both causes a treasure chest with a Piece of Heart to appear.

The Legend of Zelda: Oracle of Seasons
A Dodongo appears as the boss of Snake's Remains, which resembles Moon in shape. To damage it, Link must first feed it a bomb, then use the Power Bracelet to throw it onto a bed of spikes in the center of the room. Defeating it earns the Gift of Time

The Legend of Zelda: Four Swords Adventures
A trio of small Dodongos act as a boss in the Tower of Flames. They walk around slowly, occasionally stopping to open their mouths, eventually letting out a stream of fire. While their mouths are open, they can be fed a bomb to damage them. It takes three bombs to defeat each, at which point they will violently explode. Two later appears at the end of Realm of the Heavens. Defeating them causes the Big Dodongo to appear.

The Legend of Zelda: Twilight Princess
Dodongos appear as enemies in Goron Mines and a few other locations, now looking like crocodilians with gecko-like feet. Both their feet and their weak tails now glow orange. They have the ability to crawl up walls, typically doing so on surfaces to which the Iron Boots are magnetically attracted. Likely due to the dungeon item being the bow and bombs not being available until Darbus is saved, arrows can additionally be shot down their throats while they inhale to prepare flames.

CD-i games
"Great! I can't wait to bomb some Dodongos!"

- Link

Dodongos appear as enemies in both Link: The Faces of Evil and Zelda: The Wand of Gamelon. They appear gray in both, and can be defeated by throwing a single bomb at them. They are also defeated if caught in the blast from an exploding one. The sword also works, but requires a large amount of hits. In the introduction of the latter, Link specifically looks forward to bombing some while he travels to Gamelon.

Other appearances
Dodongo was used to represent a section titled "Dodongo dislikes:" in the magazine Nintendo Power. The section noted gaming features commonly viewed as negative, and was partnered with a section called "A winner is:" which referenced the line "A WINNER IS YOU" from the game .