Slitherhawk

Slitherhawks are dragons mentioned twice in "How to Speak Dragonese". There is no physical description, but evidently they are edible.

Hiccup first glimpses a couple while being taken to Fort Sinister as a prisoner by the Romans. He notices that the closer they got, the less animal life was around."The reason for this was clear when they spotted two dead Slitherhawks all tangled up in a gigantic net, hanging from a cliff face."Later, the Fat Consul is served up a variety of dishes, one of which includes Slitherhawk.