Changing Heat Metal to a different material?

[TigerT20]

I'm currently prepping a Dark Sun-esque campaign that has little to no metal. As a result, this makes the Heat Metal spell unusable. I was wondering what some good changes might be.

These are my first ideas:

Ignite Wood - the same but for wood

Warp Wood - simply makes things unusable, no damage.

What are some over ideas?

EDIT: Ok I would like to make clear that while the campaign pulls from Dark Sun (because cannibal halflings is a genius idea and I love them), it isnt actually taking place in Athas. Just to be clear.

[col_impact]

If a campaign makes one spell unuseable, just pick another.

[Democratus]

Warp Wood used to be a spell. And it sounds like a great solution.

Wonder where it went.

[KorvinStarmast]

I'm currently prepping a Dark Sun-esque campaign that has little to no metal. As a result, this makes the Heat Metal spell unusable.
==
What are some over ideas?

Use other spells. There are a lot of spells in the PHB. Something like 200? (I seem to recall that with XGtE and PHB there are something like 260 spells).

Think about this for a moment.
Fireball is an iconic spell.
But there are fire immune monsters.
So what's a wizard to do?
Use other spells.

[Scripten]

I agree that the best idea would be to keep things as they are and let your players make their choices under constraint. Isn't metal merely very rare and valuable in Dark Sun? It seems like that would actually make Heat Metal stronger in cases where the party fights NPCs wielding high-end gear, balancing the opportunity cost with niche utility.

EDIT: That all being said and because I personally dislike thread replies that don't actually answer the OP, Warp Wood would be a good alternative, assuming that wood is as prevalent in your setting as metal is in more traditional ones.

[Chronos]

The original purpose behind Heat Metal in the original source (i.e., where the D&D writers got it from) was as a way of enforcing a no-weapons rule in the presence of a powerful NPC. In a standard setting, it works pretty well for that, since most weapons are made (at least in part) of metal. Now, in Dark Sun, there's no one dominant material for weapons, so you can't cover everything that way, but you can at least get some of them. One common weapon material in Dark Sun, IIRC, is obsidian, and that fits thematically with heat in its own way. So I'd allow a Heat Obsidian spell.

[KorvinStarmast]

The original purpose behind Heat Metal in the original source (i.e., where the D&D writers got it from) was as a way of enforcing a no-weapons rule in the presence of a powerful NPC.

Not quite. From Eldritch Wizardry(TSR, 1976, p. 22). The original source. . Disabling an armored opponent was a prime intent behind this spell.

Heat Metal: A spell which enables the druid to cause metal objects of ferrous nature to become
progressively warm, hot, and then searing hot. The amount of metal which can be affected by
this spell is a function of the level of the druid using it. For each level he has attained the druid
can affect approximately 200 gold piece weight of ferrous metal. Flesh in contact with the metal
heated by this spell suffers burns and is accordingly damaged.
Fire resistance negates this effect.
Metal stays at the searing temperature for two turns (the first of which will blister a hand
and make it unusable for 1 day or cause 1-2 points of damage to the other parts of the body, except
the head which will take one point of damage and cause the person to become dizzy), the
second of which will cause a hand still in contact with the metal to be severely burned and
unusable for 1-3 weeks, cause an additional 2-3 points damage to a body in contact with the
metal, and inflict an additional two points of damage to a head in contact with the heated metal
- as well as causing the creature so affected to become unconscious for from 2-8 turns.
Range: 3".

Emphasis mine.
I like your idea on heat obsidian, though, and something in the Game of Thrones is kicking around in my head as I ponder this.

[Chronos]

...Huh. I was thinking of one of the short stories in the Thieves' World anthology (i.e., not a D&D book, but a book that D&D authors got their ideas from), but on double-checking, that was from 1979. So I guess that in this case, it did show up in the game before it showed up in fiction (unless there was some other earlier fiction that they both took the idea from).

[Tanarii]

Not quite. From Eldritch Wizardry(TSR, 1976, p. 22). The original source. . Disabling an armored opponent was a prime intent behind this spell.
Emphasis mine.

That disabled folks that wear metal helmets, not generally armored opponents. And while you may think any sane heavily armored warrior would also wear a helmet, Hollywood has taught me otherwise.

[KorvinStarmast]

...Huh. I was thinking of one of the short stories in the Thieves' World anthology (i.e., not a D&D book, but a book that D&D authors got their ideas from), but on double-checking, that was from 1979. So I guess that in this case, it did show up in the game before it showed up in fiction (unless there was some other earlier fiction that they both took the idea from).

I loved those books, still have all of them. :-) So, is that Hanse Shadow Spawn, or Shadow's Pawn?