Hyena

Hyenas are an odd carnivorous animal mentioned in the Dragons: Race to the Edge, Season 4 episode, "Saving Shattermaster".

Description
Hyenas are not seen in the How to Train Your Dragon Franchise, but are mentioned once. Specifically their "gizzards" are mentioned. This is a bit of a misnomer, as a "gizzard" actually refers to a digestive organ of birds (and a few other creatures).