Question: Based on a local legend, this species of dragon can't fly, but instead covers itself in flame to protect itself from hunters. 

With as little magic as possible, would something like that be possible? 

**More details about the creature:**

* It's about twelve meters long, nocturnal carnivore and is said to have thick scales.
* The flames are not a constant effect, the creature only uses it to scare off hunters.

My question is: **How could a creature like this exist?**

Magic is allowed, but I'm trying to avoid using it as much as possible.

Answer: 
It is a legend that they are covered in flame. No real creatures get covered in flame. But what if they just look like they are covered in blinding bright flames? That happens. Maybe the dragons are **bioluminescent?**

[![bioluminescent ostracod](https://i.stack.imgur.com/wZK8s.jpg)](https://i.stack.imgur.com/wZK8s.jpg)

<http://www.bbc.com/earth/story/20160526-the-organisms-that-glow-brighter-than-any-other>
A cardinalfish (Apogon sp.) spits out an ostracod after it triggers a flash of bioluminescence (Credit: naturepl.com/Alamy Stock Photo)

> 
> But Gerrish has found that the threat of attack provokes the most blinding >bursts of light.
>  "The brightest luminescence of the ostracod is produced when they are
>  preyed upon," says Gerrish. "The ostracods release large amounts of
>  both luciferase and luciferin, which mix and light up the outline of
>  the predatory fish."
> 
> 
> This flash-bomb tactic could be some of the brightest bioluminescence
>  in the ocean.
> 
> 
> 

So too your dragon. It is not on fire, but produces a fire colored flashbomb effect when under pressure. Hopefully it makes use of the time bought to counterattack, or slip way.
The question is borderline closeable with *"unclear what you are asking"*. I'll fill in the gaps with wild assumptions from the top of my head.

For example, if the beast uses this strategy to escape hunting, then it is preyed upon, either by other animals or by humans.

Also, of the creature evolved such a specialized form of defense, it was probably *in lieu* of the usual defenses, i.e.: camouflage, speed, flying (mentioned in the question), a hard carapace etc.

The trope that they won't get you if you are on fire may seem like genius at first. It was probably invented by [Dan McNinja](http://drmcninja.com) circa 2006.

![Duh](https://i.stack.imgur.com/3i0Ty.jpg)

However, while this solves one immediate problem, it has some limitations, and also introduces a number of other problems.

* If the predators are humans, they can just fill the beast with spears and lances from a distance and wait for the fire to die out after the creature itself does. So the fire coat is only useful until hominids learn how to make tools.
* This creature cannot live in environments rich in flammable plant matter. Woods, forrests, savannahs... Those ecossystems would be devastated by the mere presence of such a creature. They would quickly be without food for themselves in such places.
* The creature therefore would live in deserts or wastelands, preferrably hot, sand deserts. In such places, water is usually rare, which introduces another problem...
* The creature needs to **drink a lot**. Even if you handwave its metabolism so that it thrives with internal temperatures in the hundreds of degrees through magic, any water and other fluids inside the creature will become hot, pressurized gas. So either the creature keeps continuously venting steam, or they will resemble giant walking puffer fish. If the latter, then they are walking pressure cookers and may explode violently if they get hurt in certain ways, or if they stop venting. This is a serious hazard... Exploding pressure cookers can destroy kitchens and kill people in real life.
* This is even more troublesome for the creature because if they have access to large bodies of water, they risk falling into it and dying out of thermal shock; If there is little water, they may vaporize it while they drink. In the very least the steam coming out of their mouth may temporalily blind them after a sip. Rains may be harmful or lethal.
* They will have a hard time hiding while they sleep. In fact, they broadcast their presence at night. Predators will take advantage of that. Even if they do manage to hide, they will leave very evident tracks. During day or night, whatever they prey on will be warned of their presence with plenty of time to try an escape.
* Last but not least, if they produce flammable methane in their bowels like many animals do... Let's say that each time they defecate or pass gas will lead to explosions. If they have cloacas, then each copulation will be a very literal bang.

---

If you still want to go with such a creature, just remember that combustion needs fuel, relatively high temperatures and oxygen (or an alternative oxydizer) to be stable. You can get the latter from the atmosphere as long as the creature doesn't get into a tight place. The other two, fuel and temperature, could only be provided by magic. That, and the ability to withstand the fire, are the minimal magic requirements - though you may want to consider the bits about water that I've mentioned for magicking away as well.