Two-Headed Gormatrons are a species of dragon that appear in The Incomplete Book of Dragons.
Like the name suggests, Two-Headed Gormatrons have two heads. The two heads, however, appear to be at opposite ends of the body. It is unclear where its posterior end lies. It does have two wings and two tails, and two pairs of legs. The image of a Gormatron shows it to be a purple color.
One would think they would have an intellectual advantage over other dragons because of that, but alas they do not. The two heads can be at odds with each other and can spend days trying to go separate ways. This indecision could leave these dragons vulnerable, yet they still survive, possible because they don't smell very good or taste very good. They are also said to be not very smart.
Two-Headed Gormatrons sided with humans during the dragon Rebellion.
Two-Headed Gormatrons rate a "6" in Disobedience, and are trainable. They serve as Riding Dragons. It appears that the Rider sits in the middle of the body between its two heads.
The Two-Headed Gormatron appears in this reference book, as well as the 'Dragon Key' at the back of the book.