This is a companion to Wingspan. Totally not my ideas, I just wrote it out. All credit goes to Toothless-the-nightfury.
Yeah, Toothless can shot out oxygen/acetylene-fueled flames that will explode upon impact and will instantly incinerate anything. It works in fights (example: bringing down the Red Death!) Not so much flying into it. That WILL singe your hair. Of course, it can be used in other ways….
#1: When That Sword Will Just Not Melt
"COME ON!" Hiccup yelled at the most stubborn of metal hunks he'd ever had the pleasure of shaping. "Gobber, what is this stuff?"
"Dunno, found it flying on another island. Sturdy, huh?"
"Oh, very." Hiccup sighed. "Our fire's not hot enough to melt it at all."
"You're probably just bein' too impatient. Give it a minute."
Toothless, sensing his human's frustration, lumbered over, trying to avoid knocking into furniture. He turned his eyes on Hiccup, asking what was wrong. Hiccup gestured to the metal. "That's it, boy. Just blacksmithing issues."
Toothless cocked his head. With a metallic noise from his throat, he shot a puff of fire on the metal. It began to bend as if a giant's fist had crushed it.
"Thanks, Toothless!" Toothless wondered why Hiccup was so excited. He'd done very little. "Extra cod for you tonight."
Well, he wasn't going to argue with that.
#2: What Do You Mean You Can't Find the Tinder?
"Dad, where's the tinder stone?"
"I haven't touched it, son."
"Dad, I keep it in the exact same place. I didn't move it."
"Well, I dunno, son."
There was a pause where both looked at Toothless and wondered before Stoick asked, "Okay, well what are we going to for supper without fire?"
"We have some stew leftover…."
Stoick made a face. Hiccup raised his eyebrows. "Dad. C'mon. You go on expeditions and go weeks without a hot meal."
"Exactly. I don't do that in the comforts of my home."
"Well, we could go eat at Gobber's…."
Stoick shuddered.
"You're right, bad idea. Astrid's?"
"Well, I don't see why no…well, look at your overgrown lizard!"
Toothless had lit the fire as a way for making up for taking the tinder to draw with. He'd have to sneak in back in place later.
#3: When You Just Need to Teach Someone a Lesson
Toothless tolerated Snoutlout. He's Hiccup's family, after all. And sometimes his friend. But really, sometimes that kid just needed someone to rough him up a little.
Especially when he pulls something like this.
These Vikings like to mess with each other. Hiccup can come up with some pretty ingenious pranks himself. That was why Snoutlout decided to get him back. Toothless personally thought stealing all of Snoutlout's pants was pretty funny.
Snoutlout stealing Hiccup's leg, less so.
It's a good thing Toothless is a light sleeper and hears the oaf sneak in. He follows him, undetectable in the dark. Outside, Snoutlout gives a quiet whoop and laughs. Toothless dodges out of the shadows, shoots a bolt of flame on either side of the moron, close enough to make him feel the heat. Snoutlout shrieks, drops the leg, and bolts in the direction of his house.
Toothless retrieves the leg and has in back in its place without even waking Hiccup up.
#4: When You're Just a Little Curious
Toothless doesn't understand why humans like to burn perfectly good meat and take out all the juices he loves in his mouth.
But there's got to be something to it, since every human he knows does it and keeps doing it.
He personally had never thought of the idea before meeting Hiccup. It seems kind of unnatural, honestly. But still…the curiosity was there.
So when Hiccup gave him his fish one night, called goodbye, and raced to go meet Astrid, he set out to try it. He delicately clamped his teeth around one delicious cod and dropped in on the ground. He lit it on fire and waited before pushing his water on it and extinguishing his flame. He again clamped his jaws around it and swallowed.
Ugh!
That's what he thought from the beginning. Still, he had tried it.
Now he had to deal with the flame licking the wall.
He put it out and hoped Hiccup wouldn't notice the scorch marks.