Threadtail

The Threadtail is a dragon that first appeared in How to Train Your Dragon 2. Its name was revealed in Rise of Berk.

Description
Don't touch! This dragon can secrete a poison through its skin when it senses danger. The only problem is the Threadtail is allergic to it too! It spends most of the day rolling around in Dragonberry bushes to relieve the itching.

Trivia

 * The Threadtail's design was used for the Hobblegrunt in School of Dragons.
 * The ability to secrete poison through its skin is similar to the poison dart frog.