In designing the dragon, production designer Doug Chiang wanted to create something unique in film. The designers looked at bats and flying squirrels for inspiration, and also designed its tail to allow underwater propulsion. As the beast is Beowulf's son with Grendel's mother, elements such as Winstone's eyes and cheekbone structure were incorporated into its look. The three primary monsters in the film share a golden color scheme, because they are all related. Grendel has patches of gold skin, but because of his torment, he has shed much of his scales and exposed his internal workings. He still had to resemble Crispin Glover though: the animators decided to adapt Glover's own parted hairstyle to Grendel, albeit with bald patches.