Ramsay the Vortisaur (scientific name: Pterosauria vortexfera) from the Doctor Who Big Finish audio: Storm Warning.
My design is based off of a combination of pterosaurs (and a few dinosaurs), namely Quetzalcoatlus (main body, wings, face), Ludodactylus (teeth and main head crest), Velociraptor (front arms), and Diplodocus (tail).
Personal headcanons:
1) Vortisaurs can change colors to match the different colors present in the Time Vortex/blend into the Vortex, similar to the way chameleons blend in with their environments. In a similar vein, Vortisaurs imitate star clusters, nebulas, and even parts of galaxies across their bodies from the various times and places they’ve been present in.
2) Vortisaurs are like the albatrosses of the Space-Time continuum, in that they can travel for months, years, or even centuries (relatively speaking) without stopping to land.
3) Vortisaurs are facultatively bipedal (can run on hind legs when they need to, but are generally quadrupedal for the most part (when they do land)).