What is the most dangerous dragon in how do you train your dragon?

Related questions

1. Why are the targaryens called dragons?
2. Do bearded dragons like to cuddle?
3. Who is the dragon god?
4. How were the dragons born in Game of Thrones?
5. Did drogon leave Daenerys?
6. What does a golden dragon mean?
7. What are the names of Daenerys dragons?
8. What is the name of a female dragon?
9. Why did Khal Drogo die?
10. What are the genders of Daenerys dragons?

Tags

1. #train
2. #bewilderbeast
3. #dragon
4. #toothless
5. #hiccup
6. #series
7. #biggest
8. #shown
9. #rarest
10. #breed
11. #night