Toad Dragon

Toad Dragons are huge, repulsive, primeval creatures that are a mutated off-shoot of the more pure-breed Dragons. These creatures are known to be very few in numbers, and are usually confined largely to the trackless, otherworldly fens known as Cold Mire under the coruscating skies of the uttermost north. These colossal beast are near mindless, violent and almost impossible to kill, with a dire reputation in the legends of many of those living within the Northern Waste.

Their naming comes directly from their odd appearance and raw physical power, with some mistaking these creatures as a distant relative to the reptilian beast of distant Lustria rather then the true and ancient lineage of dragon-kind. The strength of a Toad Dragon equal as amazing as their ravenous appetite, with a tainted breath so corrosively foul that it would liquidate flesh and wither steel in mere moments.

Those it does not devour are smashed flat by its hulking body as it crawls across the earth. When it eats, the beast would generally spring out its long and barded tongue onto an unsuspecting victim with terrifying speed and drag it unto its maw to be digested. One of the most famous Toad Dragon to ever live was the Toad Dragon Bubebolos, the legendary mount of Tamurkhan the Maggot Lord.

Source
Warhammer: Monstrous Arcanum -- pg 31