I had This Idea and posted it on the creativity forums, But id also like a bunch of feedpack so im crossposting it here.

Hopefully thats allowed let me know if its not and ill take down one of them (probly the creativity one)

anywho

IDEAS?!

So, as far as fluff is concerned i cant make any remotely believable story as to why you can mutate fire/water/air stuff. Maybe water stuff but definitely not fire and ice stuff. so ive determined a few key points to Nature Mutations.

Stuff like, Randomly Generating Mutation Effects

D100
1-10 = Complete Body Mutation (The Host is completely transformed into the desired Mutation)
11-70 = Host Gains ability (Host gains a basic mutation)
71-100 = Host Gains Two abilities (Roll for two abilities)

And then stuff like

Roll 1d8

1 Natural armor +2 to Ac
2 Regeneration 1 Hp Per Turn
3 1d4 Poison Breath Weapon
4 Animal Instincts (+2 to Reflex, +2 to Spot, Listen and Search)
5 Attacks inflict 1d2 poison damage
6 Resistance to Nature Magic/Poison
7 Animalistic Features (Roll 1d6 for Str,Dex,Con and so on, Then add 2 To that stat)
8 Extra Limbs, Creature gains another Basic attack per turn with a +1 base attack (As well as other modifiers)

If you happen to roll a 1-10 you get an extreme mutation out of this category. (i still have to work the math out but ive been at work for a bunch). So if you get an extreme mutation lets say.. for regeneration, Then regerate 4hp per turn perhaps? Extreme mutation for the breath weapon? you gain a 2d6 Poison breath weapon or something of the kind.

In extreme mutations there would be some drawbacks as well (So that the CR doesnt change drastically) Like a drastic reduction in abilities or skills.

Well have to wait and see what i come up with for some other stuff tommorrow

There can be plenty of reasons that this would be believable in a world rift with the taint of some widespread plaque who's catastrophic implecations mention of the break down in the physiology of elements. I would start with the four basic kind such as air, water, fire and earth and throw in something about a rock paper scissors effect happening among the molecular structure of the building blocks of matter that have somehow been transfigured to a different state of being. This screams d20 modern. In effect you could keep your CR rating and expand a story and plot to infuse the linnear parasites as finding new hosts to form a quantum intellectual property to it. Adjoining the "crystals" would bring about the effects of new powers.

I like that, Im going through it and reworking it over and over until it feels right. Will post more stuffs soon

So, im still working out the kinks of creating them from scratch with a randomizer. But ive got a little tidbit for you and how they work.

This is the sample encounter ive been working on the most.

So you take a bear.

Hp20, Ac 17,
All Scores 13
CR1

And you infect it with a Growth aligned Parasite, It gains a few new abilities

HP 22, Ac17
Str 14, Dex 14, Others 13
Minor Regen, 1hp per turn regen

Or, something goes terribly wrong with the fusion (or terribly good, either way)

And it becomes this, Basically turned into a walking poison/venom factory.

Venomscreamer Warbear

Hp25, Ac12
Con 18, Str 8, Dex 10, Others 11
Regen 1 Hp per round
1d6 Poison Breath Weapon

Fluff: "The sound of dripping asails your ears, you turn around to see a shambling, starved bear dragging itself towards you. You hear it cry out in pain, An agonizing howl that seems to come from more than one mouth. its green eyes contrast to its jet black fur. Its maw is a ruined mess, with a missing lower jaw and rotted teeth, Three long thick tongues spill out of its throat and drip with green and purple slag"

(note these are meant to be bare bones, CR 1-2 Creatures. The real meat and potatoes of this idea will be like... CR 10 Dragons that become completely different creatures.)

But yah, Some more stuff soon