Our group realized we had a confusion on how mutant powers really work. Do we use the actual stat value or the stat bonus?

Here is an example (almost all powers are like this):

Page 37 - Cockroach - Eau De Roach - "Attack: Constitution + your level vs. Fortitude"

My character is level 4 and has Constitution : 18 (+4)

So which is true:

  1. my attack roll is 18 (Constitution value) + 4 (Level)= 22 + 1d20, or

  2. my attack roll is 4 (Constitution bonus) + 4 (Level) = 8 + 1d20?


2 Answers 2


Use the stat bonus

Assuming you have an 18 (+4) constitution and are level 4, a constitution-based attack would be 1d20+8 for the attack roll.

From the core Gamma World book, page 17 (emphasis mine):

Attack Rolls: ... Roll a d20 and add your attack modifier (your level + your ability modifier) for the attack. ...

To my knowledge, your hit point total is the only place you ever use the stat value (called an ability score) rather than the stat bonus (called an ability modifier). The ability scores are there because they do additional things in Dungeons & Dragons, which Gamma World is based on.

  • \$\begingroup\$ We thought it might be this, but it's strange how the damage part of each power explicitly says "stat bonus" but the attack part only says "stat" \$\endgroup\$
    – SteveED
    Commented Nov 7, 2012 at 2:11
  • 1
    \$\begingroup\$ @SteveED: It was written in a bit of a hurry, and they weren't always sufficiently careful about copy & pasting things from 4e. \$\endgroup\$
    – Oblivious Sage
    Commented Nov 7, 2012 at 2:12

I'm interpreting this as Con value + level vs. Fortitude, with no d20 roll. So in the example above 18+4 = 22, and it's as if you rolled 22. That's a fairly solid attack, especially considering that the stat for your origin is either 18 or 16 at the lowest. But it would be a static number every time you use the same attack. Kinda takes the fun out of rolling.

It may be just a series of editing mistakes, but it seems very consistent. In describing the attack they often spell out Constitution, then to describe the amount of damage just below it they'll write Con modifier. And it's consistent from the rulebook to at least 2 of the expansions, Famine in Far-Go and Legion of Gold. Both of them add new origin types, and both of them have attacks described that way. It also took me a minute to figure out that Fort/Ref/Will are now like AC, static numbers that you don't roll like a saving throw.


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