- "Carbon Dog becomes Diamond Dog after taking damage of several hundred HP. Now it's your turn to suffer. DD is hard. Use Multi-Bottle Rockets right away before it puts up its counter shield. Also use shield killer."
- — EarthBound Player's Guide
The Diamond Dog (ダイヤモンドドッグ, Diamond Dog) is a boss in EarthBound, the second and final form of the Carbon Dog, and the final "Your Sanctuary" boss. This form of the Carbon Dog is stronger; however, its ability to breathe fire is now replaced with the ability to use powerful Diamondizing bites, which as the name of the attack implies, has a strong chance of diamondizing party members. When this form is first activated, the boss gains Shield β, and will reflect the move that caused its transformation provided it was physical.
The Diamond Dog is able to use PSI now, along with standard biting attacks. It may also howl, which has no effect. Upon defeating the Diamond Dog, Ness gains entrance to the final Your Sanctuary location, Fire Spring.
|Text Displayed||Power||PP||Possible Effects|
|Used a biting attack||Low||N/A||Damages one target|
|Used a biting attack||High||N/A||Damages one target|
|Bit hard||Low||N/A||Damages one target, chance to Diamondize|
|Emitted a glorious light||N/A||32*||PSI Flash Ω|
|Shield β||N/A||10||Physical Counter Shield|
- Diamond Dog's name appears to be a reference to the 1974 David Bowie album Diamond Dogs and/or its title track.
- The Diamond Dog has the biggest experience points reward in the entire game - a whooping 337k points.
- The transformation from Carbon Dog to Diamond Dog refers to the process of carbon becoming diamond through exposure to extreme heat and pressure.
- Similar to Titanic Ant, the first sanctuary boss, Diamond Dog has two different attacks with the same text.