@Cuddles:
Hey, I was at work, and I noticed the two-headed dragon was called a Zippleback (couldn't remember it before).
Considering that that dragon uses gas and sparks to ignite things, do you think it was called Zippleback because 'Zippoback' would've been copyright infringement?
Here's a quote from pg 44 of the artbook (happened to just read it a couple minutes ago!):
"This dragon [the Hideous Zippleback] does not breathe fire, technically. Instead, one head emits a flammable gas while the other strikes a spark to ignite it into a flame. Perhaps a more appropriate name would have been the Zippo-back?"
And @Sesshy:
! Perhaps it was because Hiccup planned to leave in secrecy. Without Astrid reporting him, he would have simply been written off as "disappeared for unknown reasons". That doesn't sound nearly as treacherous as "eloping with dragon friend", which might have provoked some hostile reactions.
! And as for why he abandoned the decision to run away after being caught by Astrid– Even she, the most determined of his peers, was able to accept and even admire a dragon. As a result Hiccup might have realized that there were more possibilities than simply running away, and so decided to stay "one more day" and weigh his options.
! Just my 2 cents!