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.
**"Would something like that be possible?"**

You're asking about the eternal flames, but you're forgetting that it's a flaming, nocturnal carnivore. That won't work. Its prey would see it coming from miles away: it's nighttime, and this huge thing is on fire! Your dragon would starve.