The Big Dodongo only appears once in the game and is found at the very end of the Realm of the Heavens. When the four Links enter the arena where he is fought, they will first encounter two regular Dodongo which must be fought and destroyed using Bombs (similar to the battle in the Tower of Flames). However once these enemies are defeated the Big Dodongo will suddenly appear in the middle of the cloudy arena and start stomping around. Its method of movement and attack is identical to that of the regular Dodongos, meaning it only moves at cardinal directions and attacks by opening its mouth and spewing flames, but his extreme size makes it a lot harder to avoid than the standard foe.
As well as causing a large amount of damage if it hits any of the Links, the Big Dodongo is entirely invulnerable to normal bombs. Even those tossed in his gigantic maw will have no effect on the beast. Luckily, the defeat of the first two Dodongos causes four chests to appear; each containing a Level 2 Bomb upgrade. These huge bombs are the only thing that can defeat the Big Dodongo. Once obtained, defeating the Big Dodongo is the same as defeating the smaller variety; throwing or placing a Level 2 Bomb in its mouth when open will cause it to explode inside the monster and cause damage.
The Big Dodongo is the only boss in the game that requires the use of a Level 2 item upgrade.
Exceptionally large Dodongos also appear in Majora's Mask, but they are just deemed to be exceptionally large versions of the regular enemy.
The "Degu" in this monster's Japanese name is commonly translated as "Big" but is also used in the names of other stronger varieties of normal enemies such as the Armos Knight.