What would happen if Flowey came to the HTTYD world? (This story needs serious work)

Another HTTYD and Undertale crossover.What if Hiccup, Chara, Asriel and Toothless switched roles? What if the dragons were the ones trapped underground?This is about a stubborn viking boy who wants to prove to his village that he's not useless, but ends up falling into the dragons watery cave. Raised by the gentle beasts, can Hiccup prove that the dragons are harmless?

A HTTYD and Undertale Crossover. What if Hiccup, Toothless, Chara and Asriel were swapped? What if the monsters were never trapped underground? This is the story about a child who befriends humans greatest enemy-a monster. Together, can Chara and Asriel save each others kind? Or will they perish? (sorry still not great at descriptions XD)

The Dragontime is coming, And only a King can save you now. The monsters of the underground emerge from the Murderous Mountains (specifically Mt. Ebott), only to find themselves in a world at war. Stumbling onto the Singing Sands of the Ferryman's Gift, and Alvinsmen only minutes away, they have to figure out how to deal with this strange new world. And probably stop a war... heh.

What if Hiccup fell down instead of Frisk? TW: Blood and death.

Monsters thought life in the Underground would be a gloomy nightmare, but dragons, loyal partners in the war, had joined them to bring light into their poor lives. With almost every monster having a dragon companion, the fallen human's journey would turn out to be somewhat more interesting than they could have ever expected it to be.

How to Train Your Dragon, with one big difference - instead of dragons, we have monsters. *title and summary may change*