Author's notes: so...long story short someone mentioned 'weredragons' to me and I just had to. This is a little AU about what if the dragons were able to pass on a virus similar to lycanthropy and Hiccup was infected in the arena by Hookfang. The dragons still raid them because Hiccup never told Stoick about the nest, and Hiccup transforms once a month during the full moon, under guard, in the arena.

Nobody talked about it when the full moon rolled around. The village grew silent, people cleared a path for him as he was marched down to the dragon arena, flanked on either side by the village's toughest men. His father wouldn't even look at him as he passed him at the gate, instead looking over him and giving orders to the warriors beside him to make sure the gate to the arena was locked tight.

Then they played the waiting game. Nobody spoke, nobody even breathed a word, weapons drawn. He could hear Toothless pacing and growling where he was being kept outside the arena just in case he needed to be calmed down.

It was the only reason they'd kept Toothless alive.

The moon rose, like always shining light down on the arena. Hiccup could practically hear the sounds of old battles, the roars of the dragons as they were either defeated or they killed the warrior sent in to fight them, the noise of blood splattering and staining the walls, of clanging weapons and jeers from the crowds.

The transformation was painful as always.

As soon as the moon hit him, his body started changing. Bones creaked and cracked as they morphed, green eyes dilating and narrowing as his mouth changed shape, becoming longer, teeth sharper. Nails blackened and elongated, sharpening at the end, scraping at the ground as his howling of pain became a roar, pressing himself into the ground and twisting, body turning as it became too painful to bear. It felt like his core was being ripped in two, his back arching up from the surface of the arena floor.

Make it stop, he wanted to scream, but his vocal chords no longer allowed him to speak human words, so he screamed it in Dragonese, the noise gruff and deep, unlike his human speech. His head throbbed as horns started poking their way from his skull and he whined low in his throat, but loud enough to make the warriors standing guard cringe. Make it stop!

The freckles on his body became black splotches of scales, the rustic coloured skin turning red.

There was a popping sound as his spine stretched into shape.

Silence.

The warriors waited. The moon shifted overhead, half obscured by cloud but the damage was done. When no noise followed, they looked at each other, concerned, before they turned away from the arena door.

Just for a second.

Tiptoeing towards the metal bars that surrounded the arena like a cage, they peeked in, spear and mace drawn, shield erect, expecting to see a small Nightmare pacing the arena like they regularly did.

There was nothing in there.

As one, the warriors looked to each other, alarmed, and ran to the arena gate, throwing the latch open. The moon was completely obscured by the clouds, covering the stage in shadow as they poked their heads in before creeping into the kill ring.

The gate shut without anything to hold it up.

Snotlout dropped his mace and shield and grabbed hold of the bars, shaking them before he turned to Tuffnut. "They won't budge!" he exclaimed, feeling his heart beginning to pound in his chest. He didn't want to be in here, stuck with his freak of a cousin.

"Well we gotta do something! I'm not waiting to-"

Tuffnut was cut off by a clinking sound, shifting his gaze away from his best friend to glance around the arena, a startled noise being drawn from his throat as he stepped back towards the other viking. Moonlight shone down into the ring, casting shadow across its floors and a distinct shape. Snotlout paused where he was trying to yank the door open from the inside, turning his head.

There, above them on the 'ceiling' of chains and bars obscuring escape, was Hiccup. The weredragon's neck craned down to look at them, yellow-green eyes wild and narrow, intelligent. He lowered himself to the ground, tongue slithering out to lick at his leathery lips as Snotlout picked up his mace and shield again, starting to shake.

Hiccup grinned nastily.

Dinner was served.