Gamma World 1st Edition lists it as the BLACK RAY GUN, mentions "Death Ray" as the projectile it shoots and explains that it is "the ultimate hand-held weapon", which inflicts "instant death on living targets not protected by force fields" (which completely nullify the effect of the gun), and doing no damage to non-living targets. How cool is that :-) ?
Now I am not a proponent of instant-death effects but rather prefer my games in this regard to be a bit more influenced by randomness. So here we go with the revised Black Ray Rifle for Gaia Gamma:
Black Ray Rifle, Range: 25m / 50m, Projectile: Death Ray, Damage Inflicted: 6dx++-3L (completely stopped by force fields), Power Source: Internal Fusion Reactor
This is the ultimate hand-held weapon. The internal fusion reactor supplies with with continuous energy. The awesome powers use charges of which the internal reactor can hold a maximum of three. Every eight hours one charge is restored. On an attack roll of 36 another roll of d6 is required - if it results in a 1 the internal fusion reactor becomes unstable and explodes causing standard damage to every living being within a radius of one meter per point of damage inflicted. The Black Ray Rifle is completely destroyed in the process.This IMHO adds even more excitement to the weapon and replaces insta-death by a potentially huge amount of damage. And it probably also wins a prize for the Most Exotic Damage Notation For Any RPG Weapon Ever Designed.
BTW, just to refresh your knowledge of the Gaia Gamma rules: 6dx++-3L means: Roll six six-sided dice and generate a score for each die. Re-roll sixes (adding to the individual result) until some other number comes up. Take away the three lowest rolls and multiply the three remaining scores for the final damage. Example: You roll 1, 3, 4, 5, 5, 6. The 6 is re-rolled for yet another six (re-roll again) and a final 4. So your scores are 1, 3, 4, 5, 16 (6 + 6 + 4). Remove the three lowest scores (1, 2, 4) and multiply the remainder (5, 5, 16) to get a whopping 400 points of damage. Yes, I know - almost instant death :-) But there is a chance for survival. And as you will note my version of the Black Ray Rifle is able to damage non-living structures - so structural damage becomes an interesting issue.
BTW, trying my hand at the design of a revised Black Ray Rifle lead to the inclusion of new sections for Misfires and Structural Damage to the table of content, to be seen in the next release of Gaia Gamma.