Gamma Ray

 is a gun that fires a continuous green laser that slightly curves towards enemies and has a chance to poison enemies.

Trivia

 * Mean Green is a probable reference to The Hulk, who was transformed into its form by exposure to gamma radiation.
 * The Beta Ray synergy is likely named for Beta Ray Bill, another Marvel Comics character. Alternatively, it may be a reference to beta decay particles.
 * Meltdown is the only Synergy not directly related to Orbital Bullets that directly alters its behavior.
 * The Gamma Ray bears some resemblance to the Laser Pistol from the Fallout series, specifically the AEP7 model that appears in Fallout 3 and Fallout: New Vegas.
 * If the Beta Ray synergy with Irradiated lead is obtained, it changes to look like the AER9 Laser Rifle from the same games.
 * Fallout: New Vegas featured a special iteration of the Laser Rifle, the AER14 prototype, that, coincidentally, fired green lasers instead of the usual red.