Converting D&D Monsters to Gamma World, Part I

Wait...a Displacer Beast? And a dude with a laser gun??

As I’ve mentioned here recently, I’ve started a Gamma World campaign with my play group. Which of course means that you will be subjected to the occasional Gamma World article. (Not that you haven’t in the past)

I love the Gamma World game. I just wish there were more monsters. What’s a good GM to do? Well, if the title of this article is any indication, they simply need to port some D&D monsters into the setting. There is an abundance of D&D monsters out there, plus the 4e and Gamma World systems are built on the same chassis, so it should be easy to bring them over right? Just check out the image at the top from page 33 of the Gamma World rulebook… but wait. Displacer Beasts aren’t in any of the Gamma World books…

Now hold on just a minute here. While monsters can be ported from D&D to Gamma World in a pinch without any adjustment, there are some things to consider if you want the transition to be seamless. I’m going to tackle the easiest one first. Energy damage types.

Here are the D&D energy damage types:
acid, cold, fire, force, lightning, necrotic, poison, psychic, radiant, and thunder

And here are the Gamma World energy damage types:
acid, cold, electricity, fire, force, laser, necrotic, poison, psychic, radiation, and sonic. I guess I need to also add “physical” to the list to make it technically complete, though D&D doesn’t type physical damage. Anything that doesn’t have an energy type in D&D is physical damage. So I’m going to ignore that one.

Right off the bat, we have a small problem. There are 10 energy damage types in D&D, while there are 11 in Gamma World. Let’s do the easy part first; here are the ones that line up nicely:

(D&D to Gamma World)

• Acid – acid
• Cold – cold
• Fire – fire
• Force – force (notice a pattern?)
• Lightning – electricity
• Necrotic – necrotic
• Poison – poison
• Psychic – psychic
• Thunder – sonic

The only two that don’t match up exactly on that list are lightning/electricity and thunder/sonic. And really, that’s just semantics. The basic energy type behind it is the same. So what do we have left?

• D&D – radiant
• Gamma World – laser, radiation

My gut instinct is to try and line up one of the Gamma World leftovers with radiant. Problem is, they both kind of fit. I mean, “radiation” and “radiant” are practically the same word. Also, when I usually think of radiant damage, I think of “bright light” damage. Ergo, lasers also work. What’s an OCD DM to do? (BTW, has anyone taken that one? @TheOCDDM? No?)

Here’s where I come down on this one. First, the number of D&D monsters that do radiant damage are far and few between. If you do come across one, look at the type of attack that’s doing the damage. If it’s a ranged attack with one target, laser is most likely the best choice. If it’s a burst or blast, radiation is probably the way to go; I can’t really see a laser making a “burst.” Second (and this is a little tougher), we have the problem of monster vulnerabilities. What types of monsters are vulnerable radiant? By and large, undead. To solve this problem, we either have to dip into Gamma World canon (easy way) or look at the lore behind the settings (fun way). Undead are vulnerable radiant in D&D because in fantasy lore, undead creatures are abominations that can be destroyed by the holy power of a good god. That’s what “radiant” damage is supposed to represent. Gamma World has no such lore; instead, the setting is modern post-apocalypse where no mention of a god exists. So what does a member of the post-apocalypse do when they come across a zombie? Easy: hack it to pieces. And just to be clear, the Gamma World rules support this conclusion. Zombies are vulnerable physical.

Before I sign off, I need to say this: I’m not advocating strictly following this guide in every circumstance. If you have a D&D monster that you want to use, and that monster does acid (or fire, or necrotic) damage, but you think it would be cooler to make it do radiation… well, go for it! Just in case someone needs the encouragement to color outside the lines, well, there it is.