May or may not be the same as Nightmares.
These monstrosities are created from the flesh and bones of Griffons, Hippogriffs, and sometimes even Wyverns, a feat considered the pinnacle of necromancy. They combine all the terrible ferocity of the original creatures with the addition of unholy strength. They typically also have additional tusks, horns, claws, and spikes added to their forms to make them even more dangerous. These abominations are favoured by Vampires as beasts of war, partly in mockery of the war Griffons ridden by the Emperor and his knights but mostly because their terrifying appearance alone has been known to rout entire forces.[1a]