Tyrannosaurus Rex and Velociraptor are probably the best known carnivorous dinosaurs of all time. One was huge, the other pretty small. But both were extremely dangerous.
Among all the dangerous prey dinosaurs there are two that were especially feared. The famous Tyrannosaurus Rex, because of its massive size and strength and the small Velociraptor, because it hunted together with other Velociraptors and they attacked from all sides simultaneously. Whichever of two attacked, both were extremely dangerous.