Supersaurus (identified as an ultrasaur, as in Ultrasaurus; see disambiguation)is a species of herbivorous sauropod dinosaur from the Jurassic. It appeared in two Sunday strips. In both strips, it is depicted as resembling Brachiosaurus, instead of a diplodocid like in real life.
Supersaurus first appeared within a herd, driving away a pack of Allosaurus only to be attacked by the fictional "Calvinosaurus". The herd was able to do so by virtue of its constituents' huge size, which was somewhat overestimated in the strip. While actual Supersaurus weighed between 35 and 40 tons, the comic claimed that "some weigh over 70 tons". The strip also misidentified the Supersaurus' time period, claiming it to have been 140 million years ago – a time free of Allosaurus – instead of the estimated 153 million.
Supersaurus appeared once more as the potential victim of an Allosaurus. The latter attempted to sneak up on the sauropod, which was quenching its thirst by a river. However, as it neared, it was proven hopelessly outmatched by the much larger Supersaurus. The allosaur's powerlessness tied in to the Supersaurus' first appearance (see above). This dinosaur fantasy is analogous to Calvin (being the Allosaurus) wanting to quench his own thirst at a the school's drinking fountain, but unable to do so due to being intimidated by Moe (represented by the Supersaurus).