Terrorgheist
Ever wonder what would happen if you took a giant bat, a dragon, a zombie, and put the, all in a blender? Behold, the amazing product, the Terrorgheist. These things are different depending on which flavour of Warhammer you're on; in fantasy, they're basically oversized bats that have been fed vampire blood amd bound after death, while in AoS they are all long dead things brought back to life via Shyishian sorcery. In both, they are ridden exclusively by Strigioi, or Ghoul Kings, depending on the setting.