Permanent and tangible changes to player characters in 5e

[Iguanodon]

Often in the course of adventuring, the PCs end up running into something that changes their person permanently, be it a lost artifact, a curse, or a blessing from a god. Specifically, I'm thinking of the stuff that doesn't break a character. So, no permanently severed limbs, gouged eyes, and the like. This is one way that characters develop apart from just leveling.

There are the usual suspects, of course, such as lycanthropy and vampirism. There are curses and divine boons. There are also (nonmagical) diseases, but a cleric or pally can cure those so easily they're not even worth considering. Apart from that, there's... the Slaad tadpole?

How have you guys used these (or seen them used) in your games? Are there any other interesting effects I'm missing?

[lebefrei]

I have on rare occasion used both the Blessings and Boons from the DMG when I felt a character truly went above and beyond (in character roleplaying as well) when performing some task. It makes players feel special.

Beyond that I have used two other permanent effects that were both fairly well received. One character lost both arms (long story, willingly done by player) and ended up gaining a troll arm in place of one. That gave them regen (as per the ring), and they regrew the other arm, but over time became moderately ugly.

On another, a character entered into a "soul bond" with two NPCs to save their own life, and could thereafter summon each 1/week when in serious trouble (autosummons at 0hp). The player really liked that.

[MaxWilson]

Often in the course of adventuring, the PCs end up running into something that changes their person permanently, be it a lost artifact, a curse, or a blessing from a god. Specifically, I'm thinking of the stuff that doesn't break a character. So, no permanently severed limbs, gouged eyes, and the like. This is one way that characters develop apart from just leveling.

There are the usual suspects, of course, such as lycanthropy and vampirism. There are curses and divine boons. There are also (nonmagical) diseases, but a cleric or pally can cure those so easily they're not even worth considering. Apart from that, there's... the Slaad tadpole?

How have you guys used these (or seen them used) in your games? Are there any other interesting effects I'm missing?

I let my players stumble across an ancient piece of xixchil biotechnology from the time before magic, when aboleths ruled the Earths. It required 1000 gp worth of gems as fuel per usage, and required you to pick from a set of seven icons inscribed on the outside, which were drawn on paper but I will attempt to describe briefly here, and then climb inside the surgical pod before activating the machine:

[Big eyes in small face] Your eyes are replaced with huge multifaceted insect eyes. You have blindsight within 60' but are blind at any greater distance.
[Beefy arms] Gain +2 to Str, lose 10% of your lifespan (unbeknownst to the PC) from overclocking your heart
[Spidery six-limbed figure] Lose -2 Dexterity, gain 2 extra limbs on your lower torso, one with a built-in gripper (can hold shields) and one with a built-in d8 finesse piercing weapon. Can try to conceal them beneath a cloak but it could be awkward.
[I forget what] Your skin is replaced by glossy black chitin. -2 to Constitution, but gain a natural AC of 15.
[Blocky square torso] Gain regeneration exactly like a troll. -2 to Int and -2 to Cha (you feel dumber and more bad-tempered), your skin turns greenish.
[Upper torso with head circled for emphasis] Brain is extracted for later consumption, replaced by a brain stem which keeps you alive but incapacitated. This usage does not consume any gems.
[Plain circle] Rebuild your body from its original DNA template, cancelling out all wounds and physical afflications (including death and dismemberment) and reversing any biomodifications previously made.

Additional effect: if you have any modifications, your creature type is no longer humanoid. You are an Aberration and affected accordingly by spells like Protection From Evil; but you are immune to spells which only work on humanoids like Hold Person/Magic Jar/etc. Plus, people that see your deformities will be creeped out.

My players couldn't resist playing with the machine and eventually ended up discovering all of the settings. :)

[djreynolds]

Often in the course of adventuring, the PCs end up running into something that changes their person permanently, be it a lost artifact, a curse, or a blessing from a god. Specifically, I'm thinking of the stuff that doesn't break a character. So, no permanently severed limbs, gouged eyes, and the like. This is one way that characters develop apart from just leveling.

There are the usual suspects, of course, such as lycanthropy and vampirism. There are curses and divine boons. There are also (nonmagical) diseases, but a cleric or pally can cure those so easily they're not even worth considering. Apart from that, there's... the Slaad tadpole?

How have you guys used these (or seen them used) in your games? Are there any other interesting effects I'm missing?

The inspiration thing is cool. We buried a body and got inspiration for it, and can use it when ever and for what ever. Extra 1d6, IMO better than ex exp. You could throw a bane at them, that either eats up inspirations they have accumulated, or forces them to roll when the DM decides, for -1d6.