Another interesting Murphy’s Rule in D&D 3.5 relates to the rules for catching on fire and how objects take damage.
First of all, when you’re at risk of catching fire you immediately get to make a DC 15 Reflex save, and on a success you don’t catch on fire. On a failure you immediately take 1d6 fire damage and will keep on doing so until you succeed at the save. You only stop being on fire once you make the save (or, supposedly, when you die, but that’s arguable).
Objects always fail their saving throws against effects that deal damage. So, throwing a bottle of flaming oil at a wooden door will cause that door to burn until it’s reduced to ashes, right?
Well, no. Objects, in addition to having hit points just like people, have Hardness, which reduces all damage they take by a certain amount. A normal wooden door has a Hardness of 5, meaning that a wooden door will only take 1 point of damage if the 1d6 comes up as a 6. That’s an average of 120 rounds to burn through a normal wooden door with 20 hp.
Also, objects take half damage from energy, including fire. This is factored before Hardness, meaning that without the caveat in the rules that certain types of objects might be vulnerable to specific types of damage it is literally impossible to burn a wooden door.
I mean, it’ll catch fire, but it’ll just keep on burning for ever and ever.
That caveat was pretty obviously intended to apply here so that wood can be burned up, so I don’t think it counts as a bad rule.
Rules for hotter fires/being more thoroughly on fire are missing, but can be extrapolated/interpolated from the 1d6 for being on fire in the sense of someone threw burning oil on you and the 3d10 for being on [the Elemental Plane of] Fire. Admittedly “the GM can interpolate” doesn’t mean the rules are great as written, but pre-3e D&D was written with the philosophy that it’s a framework, not a comprehensive description of every physical law of the gameworld (I don’t even think the designers believed the latter, but bringing on people who were used to writing competitive rules led to that)
Anyway, I don’t think it taking 12 minutes to reduce a 2-inch thick wooden door to ashes is that bad of a bug just given how long it takes to actually burn through a log.
Murphy’s Rules are not necessarily bad rules, they’re mainly ones that interact weirdly with other rules of the game and produce weird results. Anyway, as has been brought to my attention, a wooden door taking an average of twelve minutes to burn isn’t quite as much a Murphy as I first thought.
What pushes the rules for burning into Murphy territory is the fact that there’s no time limit on how long something goes on burning beyond “When it succeeds at a saving throw.”
Now, getting enough Fire Resistance to be safely able to ignore damage from natural fires is pretty much a piece of cake. Most spellcasters can do it with a single spell slot but if wasting your spell slot on doing that isn’t your thing then you can just pick a race that gives fire resistance or getting a proper magic item.
Then you just set yourself on fire and opt to fail all of your saves to end the burning. You’re now on fire forever (or until you choose to try to save or douse yourself in water).
The problem, of course, is that every flammable object you’re carrying will also catch on fire, buuut said objects have Hardness and take half damage from energy, as stated above, so unless your GM invokes the “Things that burn should burn” rule because you’re carrying a million scrolls you should be alright. Just to be on the safe side, let’s assume we’re not carrying any equipment so as to not burn it all.
So, who has the most to gain for being naked and on fire? One might assume that it’d be the Monk due to their unarmed and unarmored fighting style, but Monks in 3.5 actually rely very heavily on magic items to pull their weight.
The one class that relies the least on equipment is actually the Druid, because of having both magic and the ability to wildshape. Your GM might argue that your spell component pouch and divine focus will be ruined when you’re on fire, but when you turn into a bear they’ll safely meld into your animal form. And with Wild Spell you can still cast spells, even though all of your spell components are now a part of your animal body, so that’s a thing?
You’re now a bear that’s on fire, and you’ll keep on burning forever if you like.
(Unfortunately, the rules don’t really account for what happens when a bear that’s on fire grapples you, but it’s pretty easy to extrapolate from the rest of the rules.)