A/N: I don't even KNOW where this CAME from, guys :P It was inspired by Stoick's line in HTTYD 'I take him fishing and he goes hunting for-for TROLLS!'

It's been my personal head canon for awhile now that when Hiccup was younger and more gullible, Gobber convinced him of the existence of trolls. Since then, although Hiccup has had a deep-rooted skepticism for anything unnatural, like Santa Claus, he wholeheartedly believes in and indeed accepts the existence of trolls, real or not real. And yes. This is coming from me rewatching HTTYD three days in a row. WEIRD THINGS HAPPEN AND FUNNY LINES STICK OUT TO YOU WHEN YOU ANALYZE, OKAY?

If Gobber had taught Hiccup one thing, it was to explore the unknown.

The boy had a natural, childlike curiosity and Gobber only fanned its flames by telling Hiccup the wildest stories.

Stoick heard them talking one day as he came to pick Hiccup up from the forge. They had been planning a fishing trip for a couple of weeks now, in which Hiccup would finally learn how to fish "like a real Viking". He had never been more excited for anything in his life and Stoick had watched the boy bounce up and down every time it was mentioned for a while now.

"And then…I realized I had no left socks!" Gobber concluded in a scary whisper.

Hiccup's green eyes were even larger than normal and he was grinning ear to ear, leaning forward to catch Gobber's story. "So they really do exist?"

"Yeah! They don't always come out, mind ya…they keep to themselves, trolls, mostly…but if ya leave a left sock lyin' around, don't be surprised if it goes missing!"

"Pfft," Stoick snorted derisively. Both Hiccup and Gobber jumped, turning to look at him.

"It's true!" Gobber insisted. "They come 'round at night, mostly…lookin' for left socks to steal…"

"Or more people to scare, let's go on, now, Hiccup, it's time for you to learn how to fish."

"Look for trolls," Gobber said slyly in Hiccup's ear as the boy turned to leave. "They like to hide out by watering holes."

"Really?"

"Really."

Stoick, who had heard nothing of the exchange, nodded and said, "Right, Hiccup. Let's go."

"But I think I've got—

"C'mon. I've got everything we need. I've done this a thousand times before." He rolled his eyes and both he and Gobber smiled and rolled their eyes lovingly at the ten-year-old.

Hiccup blew out a breath and went after Stoick.

They got to the stream fairly quickly, mostly because Hiccup kept running on ahead, with his light, agile body and Stoick had to focus on keeping up with him so the boy didn't run off to look for adventure elsewhere.

"Alright, Hiccup," puffed Stoick. "This is your net. I'm about to show you how to cast, so don't get too excited."

"What're these for? I think Gobber said they were for—

"You can't believe everything he says," sniffed a deeply disapproving Stoick. He was starting to think a place in the forge wasn't the best one for his son, who was fast growing into a teen with all the wild-eyed, adventurous innocence of a child.

"But—

"Think about that stuff he was spouting about trolls, Hiccup. Do you really think you can trust that man on anything?"

"Well, he's your friend," Hiccup said defensively. "Besides, trolls exist! And they steal your socks!"

"But only the left ones," Stoick continued in a bored voice, perfectly in sync with his son's high, annoyed one. "Give it up, Hiccup. There's no such thing as trolls." He turned away from the boy, sniffing deeply and concentrating on checking the nets.

As he did, he thought he saw movement out of the corner of his eye. Glancing up, there was nothing there but a springy patch of grass and a few creaking trees, branches bending in the early autumn wind.

"Hmm," Stoick mumbled, a suspicion creeping into his chest as he realized that the patch of grass was where Hiccup had been sitting only minutes before. Standing up, he looked around for the boy, who was enthusiastically climbing on a pile of rocks that were grouped in the shape of a skull. His small hands gripped the edge of the eye of the skull, grinning emptily down at Stoick.

"Hiccup!" called Stoick. "Get down from there!"

Hiccup slipped and just barely managed to cling onto one of the jagged rock teeth of the stone skull, hanging roughly a hundred feet above the ground.

"Oh, gods," moaned Stoick, running a hand through his hair, then stroking his beard. "Why do you do this to me, Hiccup? Hiccup! Get down from there! Let go!"

"What?" demanded Hiccup, who was trying very hard not to look down. "No, I'll go the long way down! I can climb back up!"

Stoick was torn between approval at Hiccup for being able to haul himself back up and onto the head of the skull, perching in the eye for a brief moment to catch his breath, then preparing to go again and fear that his son might not be able to make it back up.

He heard a few thuds as Hiccup climbed and then a very light one as Hiccup hit the ground.

Stoick waited for the boy to cut through the small forest and get back out on the other side, but instead, he heard his son's voice yelling. "Hey! Wait! Slow down!"

"Oh, no, Hiccup, what are you doing?" moaned Stoick, preparing to climb up himself, sticking one giant boot into the space between two of the skull's teeth.

"Wait!"

Stoick made it up to the top of a skull and saw Hiccup frantically chasing after a shadowy shape, waving a hand in the air. "I just want to see you!"

A troll?

"Hiccup!" Stoick called. "C'mon, son!"

Hiccup sighed and wandered back over to Stoick.

"C'mon, son," Stoick said. "Let's just go through the forest and back through to the lake."

Hiccup was a bit upset at losing the troll, but he brightened up considerably as they reached the stream. "I told you that they existed, didn't I, Dad?"

Stoick wasn't one hundred percent sure what they'd seen was really a troll, but he didn't want to burst his son's bubble. "Yes," he said, patting the boy on the shoulder. "You did."