Fastback (real name Timmy Joe Terrapin) is a fictional character in the DC Comics universe, an anthropomorphic turtle. Fastback is a superhero who lived on the otherdimensional world of Earth-C (now Earth-26), an alternate Earth populated by sentient animals. His first appearance was in a special insert in The New Teen Titans #16 (February 1982).

While trying to catch a bus to Kornsas City (Earth-C's Kansas City, Missouri), Timmy Joe Terrapin, a resident of the "Okey-Dokey" swamp (Earth-C's Okefenoke Swamp) in the American south, found a meteor fragment lodged in his shell, said fragment launched by Starro the Conqueror. Ironically, the fragment gave the notoriously slow (both in mind and body) Timmy Joe superspeed powers. Upon hearing of other animals across the country endowned with similar powers from other meteor fragments, Timmy joined them as the superhero "Fastback," and helped to defeat Starro. Afterwards, Fastback joined the others in creating the superhero team the Zoo Crew.

Despite his increase in physical speed, Timmy Joe Terrapin was still quite laid-back in personality and slow-witted. He was a somewhat stereotypical depiction of an ignorant country bumpkin, but often his ignorance was more naïveté than stupidity. Furthermore, he is inventive using his speed to defeat his enemies.