- "But they're just pale reflections of the true Hulk."
- ―Thor describing the Gamma Monsters[src]
Gamma Monster is a hideous creature of any type mutated by the Leader's Gamma Generator to anyone who got caught in the Gamma Dome.
Only those who are wearing special gamma-immune suits, taken an antidote or being invulnerable to radiation will be immune to the Gamma Dome inside. After Hulk destroyed the Gamma Dome transmitter, everyone who were infected turned back to normal.
- The Gamma Monsters resemble a combination of Hulked-Out Heroes, monsters and Marvel Zombies from the Marvel comics.