No matter what dinosaur book you look at, any mention of Deinonychus antirrhopus immediately means you also get an illustration of a big flock of the dromaeosaurid taking down the herbivore Tenontosaurus tilletti. And, unfortunately for Tenontosaurus tilletti, it's main claim to fame is that it's the prey of Deinonychus antirrhopus. It seems that this is the only way Tenontosaurus tilletti can get its name into dinosaur franchise: being raptor food. Such is the curse of Tenontosaurus tilletti.
Tenontosaurus tilletti was a relative of Iguanodon bernissartensis. It was about seven meters long, and most of this was a really long tail. Several specimens of Tenontosaurus tilletti have been found fossilized alongside Deinonychus antirrhopus, evoking the curse. The conventional idea is that Deinonychus antirrhopus hunted in groups to take on big prey.
For a change, here we have a Tenontosaurus tilletti kicking the feathery bottoms of a pair of Deinonychus antirrhopus. Tenontosaurus tilletti lacked any defensive adaptations like horns, spikes, or a tail club. It didn't even have the conical thumb spike of many other iguanodontians, so it would have had to make do with its entire body: its long tail would have been an effective bludgeoning weapon, its powerful beak (a common feature to the ornithopod dinosaurs, which include the iguanodontians, as well as some small running forms) could probably damage the delicate body of a dromaeosaurid, and its nine-hundred-pound body may have well been able to crush any Deinonychus antirrhopus foolish enough to get too close.
This picture was partly inspired by a post on the delightful blog of Traumador the Tyrannosaur, The Tyrannosaur Chronicles: [link]