 Critics also praised the visual effects company Weta Digital and Cumberbatch's vocal and motion-capture performance for giving Smaug a fully realized personality, "hiss[ing] out his words with cold-blooded vitriol".Francis de Wolff voiced the red dragon in the long-lost 1968 BBC radio dramatization.A dragon named 'Slag' features in Gene Deitch's brief 1967 animated film.