One of the most oft-cited pieces of advice for GMs is to modify the stat lines of stock antagonists. This became such a truism in D&D that the 3/3.5 editions of the game actually introduced character class levels for stock creatures!
But class levels aren’t the only way to mix things up with your antagonists! Why not apply mutations to your bad guys!
Mutations can be taken in a few different directions. The easiest is to simply give new or unusual abilities to your NPCs. While this is technically a mutation, it doesn’t really scream “mutant!” to players. Once you’ve attached a new ability or power, there needs to be some visual indicator that would implies the new attribute. In some cases this is pretty easy (if a creature can throw fire, it’s probably holding it before it throws the aforementioned fire), but in other cases you may need to do a bit of work (mental powers are often the most difficult, but if you look to comics for inspiration, you’ll notice that telepaths and the like almost always have some visual indicator of the use of their powers. From here, we probably ought to give some background – are these one off mutations or are they part of a new species?
Let’s build out a quick example. For this example, we’ll use the standard fantasy goblin. Low hit points and not a lot of damage potential. We won’t change those attributes, but we want our goblins to be wall walkers – they have a mutation that allows them to scale sheer surfaces and ceilings, an attribute they use to ambush potential victims. This mutation will take shape as very small, claw-like hooks covering their hands, feet, knees and elbows that result in a slight discoloration. Our mutant goblins developed this ability after spending generations in the Underdark, cut off from their other kin (and as a result also suffer the marks of severe inbreeding).
Obviously, this is a better fit for scifi or fantasy games, but you could easily work mutations into a modern day horror game! We’ll look at some mutant-based settings in our next post!