Vampire Ghouldeaths are dragons that are mentioned once in the beginning of How to Steal a Dragon's Sword.
No description is given of the Vampire Ghouldeath.
One can guess they may be a type of larger size Mountain Dragon, as the Razorwings and Tonguetwisters are. Perhaps they are a precursor to the Vampire Spydragon seen in How to Betray a Dragon's Hero and How to Fight a Dragon's Fury.
Hiccup and the other Viking novices scale a shear cliff on their way to Flashburn's School of Swordfighting, and spend the night in hammocks. During the night, Red Rage dragons attack the boys, including Vampire Ghouldeaths.