Inspired by a post AHeartForStories made on tumblr about Hiccup suddenly growing.
Astrid noticed something different about Hiccup a few weeks before it happened. As the Haddock boy explained some new maneuvers they were going to try that day, Astrid stared at him in deep thought.
His face was beginning to shape up nicely, round cheeks thinning. His hair was getting longer and surprisingly thicker. Almost thick enough to braid. Astrid's cheeks bloomed a dark pink at the unexpected thought, and she ducked her head to hide the reaction.
"All right, gang, let's go-" Hiccup was interrupted by a sudden sharp intake of breath and a rather funny noise along with it. Every eye blinked at him.
"Hiccup, did you just hiccup?" Fishlegs asked.
"I guess-" another loud hiccup jumped from his throat, echoing off the walls, "I did."
"This reminds me of the time Uncle Asbjorn hiccuped so loud a mountain came tumbling down on him," Tuffnut told.
After a while, the intrusive spasms finally stopped, much to Hiccup's relief. But Astrid could tell something else was bothering him now. He was favoring his right leg.
"Hey, are you okay?"
"Yeah, just having a little pain. I can trooper through it."
By that evening after a long day of training, Hiccup seemed to be in even more pain now in both legs. Astrid made sure he got home as she walked him and Toothless back to the Chief's hut. Maybe a good night's rest would do the trick.
Little did Astrid know, that'd be the last time she'd see small Hiccup Haddock.
"Where's Hiccup?" Snotlout complained as he leaned against Hookfang. "He's always getting on to us that we're late." He cracked his knuckles. "I'm gonna knock some of that goody-two-shoes out of him when he gets here."
"Cut him some slack," Astrid countered, "he was hurting pretty bad yesterday."
Tuffnut sniggered. "Hiccup hiccupped." He looked around, disappointed. "What? Not funny anymore?"
"Not really, bro," Ruffnut said, then a smirk crossed her face, "But a mountain falling on Uncle Asbjorn still is."
"Yeah," Tuffnut grinned like an idiot, giving his twin a high-five.
A flap of wings caught everyone's attention. Toothless zoomed through the academy entrance and touched down lightly.
"Well, look who finally decided to join us!" Snotlout remarked.
"Sorry I'm late, gang. Kinda slept in this morning. Then my pants wouldn't fit right. Must of shrunk in the wash. I had to go borrow a pair from Mrs. Ack's son. She gave me the strangest look when she saw me." Hiccup dismounted but stumbled a little on the landing. "Whoa, feels like the ground came faster than it usually does." He looked at everyone as they stared in eerie silence at him. "Why are you staring at me like Mrs. Ack did?"
Hiccup stood nearly a foot taller than the day before, towering over his friends – Fishlegs being the only one close enough to his new height. "You're starting to weird me out here, guys."
Astrid was the first to shake off the shock. "Snotlout, are you gonna make good on your comment early about Hiccup being late?"
Snotlout held his hands up, eyeing the boy who was now a head taller than him. "No, I'm good."
"Whoa," the twins marveled, slinking up to their friend and examining him in deep thought.
"Do you think he ate a magic bean that made him grow, sis?" Tuff asked, squinting at Hiccup as he circled him.
"Yes," Ruff nodded, pointing a finger skywards, "I do concur that magic beans can, in fact, make you grow taller."
Hiccup groaned, watching the twins in bewilderment and slight annoyance. "Would somebody please tell me what's going on?"
Fishlegs stepped up. "Hiccup, do you feel…different?"
"Things have felt kinda off balance, but I thought maybe it was from the leg pains I had yesterday."
They all approached him, gazing up at his tall form. "Do you notice anything different now?" Astrid asked.
Hiccup looked down at them – he looked DOWN. "Oh my thor…" and it was then that Hiccup realized why everyone was giving him strange looks.