We have GammaFinder rules for mutations as a character emphasis, and for growing mutations as your gain levels, but nothing that just lets you be a typical mutant as a 1st-level character (though standard GammaFinder characters don’t start at 1st level anyway). That seems like a gap.

So, let’s fix it!

Alternate Racial Feature: Mutant

Art by Bert Folsom

You are a mutated version of your base species. You gain one Mutant Ability for which you meet the prerequisites. Your mutation replaces the following racial feature, based on your species, as noted below:
Core Species – Android (upgrade slot), Human (bonus feat), Kasatha (natural grace), Lashunta (lashunta magic), Shirren (communalism), Vesk (armor savant), Ysoki (moxie)
Legacy Species – Dwarf (traditional enemy), Elf (elven magic), Gnome (gnome magic), Half-Elf (adaptability), Half-Orc (orc ferocity), Halfling (sure-footed)
Other Species– Astrazoan (rapid revival), Bantrid (balanced), Borai (resist energy drain), Ghoran (past-life knowledge), Haan (slow fall), Hobgoblin (battle hardened), Kalo (cold resistance), Maraquoi (blindsense), Nuar (maze mind), Orc (fierce survivalist), Pahtra (wary), Skittermander (grappler), Strix (nightborn), Uplfted Bear (limited telepathy).

New Feat

MUTANT
You do not fall within the most common genetic baseline for your species.
Benefit: Select one Mutant Ability for which you meet the prerequisites. You gain this mutant ability.

art by warpaintcobra

Filing Off the Serial Numbers
One of the advantages of using the Starfinder rules for GammaFinder is that the game comes with dozens of alien races ready to use. A GM should generally allow a player to select one of these species to represent a mutant (and if the race is humanoid, change their subtype if appropriate). for example, a kalo could be used for a mutant human who is adapted to the cold and water, losing the kalo subtype and gaining the human subtype to represent their heritage.
Similarly once a character has a mutation, GMs are encouraged to allow players to describe the character physical appearance as anything they wish within reason, even if it falls well outside the normal parameters for that species’ vital statistics. If a player wants a nuar to look like a boarfolk, with bright green hair and six tusks, that’s not really any weirder than an albino bullfolk.

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