you do understand that the T-rex was most likely the dinosaur equivalent of a *****?
according to researchers, while his bite was indeed lethal as hell, his arms and legs were so short he couldnt have hunted smaller and faster pray, leaving him to eat carcasses (according to wiki, better known as carrions I guess?).
now, while breathing fire could have made him a bit more shocking and frightening, he still would have failed to fend off a circle of raptors...
oh, and twilight can made a head explode within 2 seconds, top that T-rex!