A quetzacoatlus was a pterosaur dinosaur that existed on Planet Earth around 200 million years ago. Living in the same suborder as the similar-looking pterodactyl, quetzacoatlus also inhabited one of the worlds appearing in Wonder Boy before the Great Dying. Passing into Ghost World, the flying ghosts are often sent to attack Skyrock Mountains from the air and one even captured poet Wordsmith, dragging him back to its nest. Fortunately for Wordsmith, the dinosaur disappeared and didn't return until the human had already escaped.
Since the destruction of the staircase concocted by the Wailing Sisters of Witchery World, there is still nothing to stop the quetzacoatlus troops attacking the living worlds, despite Shion's assertion that they were now quite safe.