Frostbrood Vanquisher is a Scourge flying mount, frost wyrms made from the reanimated bones of dragon carcasses the Scourge have been excavating in Dragonblight and Icecrown. Death Knights fly on one while on the quest  .
As of Patch 3.3.0, players can earn a Frostbrood Vanquisher mount. Players receive and by completing the Dungeons & Raids achievements and , respectively. These are 310% speed mounts, the fastest currently available.