The Tavern

Maybe i find the idea of species specific mutations interesting, but perhaps they're not a good idea since they only have a chance to occur in 1/27 of games.

(Gargoyle and Tengu only)
Shrunken wings: Your wings are shrunken.
1 : Your flying ability exhausts you. Permanent flight is disabled.
"Your wings crumple and soften!" / "Your wings regain their form."

(Gargoyle only)
Rusted: Your skin is rusted.
1: Innate AC is halved.
"Your body erupts in rust!" / "Your rust disappears!"

(Octopode only) (Can't be gained while in water)
Anti-swimming
1: (Suppresses amphibiousness)
"You feel your gills close up!" / "Your gills regain their function."

(Grey Draconians and Gargoyles onyl)
Anti-unbreathing
1: (Suppresses non-breathing) (Suppresses Grey Draconian swimming)
"You feel breathful."

And how about a few good ones

(Demonspawn only) (Removes itself after gaining last demonspawn mutation)
(Mutations are still gained in the same order, so high-tier demonspawn mutations still happen later)
Accelerated demonization: Your demonization is happening faster.
1: Chance to gain demonspawn mutation on level up is doubled.
2: Always gains a demonspawn mutation on level up.
"You feel a rush of demonic growth." / "The demonic rush slows/subsides."

(Felid only)
Hand manipulation: Your paws can grasp objects a little/a little better.
1: Allows the equipping of cloaks.
2: Allows the equipping of cloaks and hats.
"You feel more sure with your paws." / "Your paws feel numb."

(Draconian only)
Big breath: Your lung capacity is bigger.
1: You can use your breath weapon twice in a row before losing your breath. (There must not be any action between your first and second breath)
"You feel your chest expand." / "You feel short of breath."

Personally I'm not a fan. Some of the reasons I play those species is because they have those mutations. If I wanna play a fast, evasive, fragile, destructive magic species, I play tengu. If they lose that, they're more like a fragile destructive magic species. I'd rather just play a Deep Elf then for and easier time with learning spells. Losing the mutations that differentiate them would (in my opinion) just be really aggravating.

my idea for a mutation is also a god nerf (fuck ru)

felids: smartpaws
gain 1 int for every paw you have

what if people had easily detachable body parts, and you could like, put your two arms together into one bigger arm to reach something on a really high shelf. but sometimes your smaller parts would fall off and you wouldn't notice. so say you're walking down the street and your ears fall off, and a few minutes later someone comes running up to you and tells you "hey you dropped an ear back there" but you can't hear him, because you have no ears. that would suck

yes a single-level mutation that almost nukes what defines gargoyles is definitely a good idea (how does rock rust anyhow)

Rock can't rust, but how about...

Like Plok, the SNES platformer. You used your arms and legs as boomerang-style ammo, but they were also your hit points. When you launched your legs, you couldn't move any more. When you lost 20% of your health, you lost your right hand, and could only have 3 projectiles instead of 4. This mechanic could fit in crawl somewhere.

Mutation: Oozing Goo

Effects:
LV1 Enemies' melee attack speed is slightly reduced.
LV2 Enemies' melee attack speed is moderately reduced. You movement speed is slightly reduced. You leave a trail of goo that may slightly reduce other creature's move speed.
LV3 Enemies' melee attack speed is moderately reduced. Enemy melee weapons may stick to you (disarm). You movement speed is moderately reduced. You leave a trail of goo that may moderately reduce other creature's move speed. Weak creatures may be immobilized.

Mutation: Thunder Farts

Effects:
LV1 Makes a moderate sound and fires out a bolt of electricity.
LV2 Makes a loud sound and fires out a stronger bolt of electricity. May sicken hit creatures.
LV3 Makes an extreme sound and blasts a cloud area of electricity. May sicken and/or immobilize creatures.

Mutation: (Very) Ugly Face

Effects:
LV1 Makes targeted enemy flee. Range 2. Causes exhaustion (depression).
LV2 Makes all enemies within Range 2 to flee. Causes exhaustion.

Terrifying Maw: "Your mouth has monstrous biting mandibles that sometimes make it hard to speak clearly." Very damaging auxiliary biting attack, at the cost that reading scrolls/casting spells/using invocations sometimes fails. Probably incompatible with Vine Stalkers.