It's easy to argue the lack of size of the T-Rex. Its place on this list has more to do with its destructive behavior than its sheer size. But there is no question it is a giant monster. At nearly 20 feet tall and weighing eight tons, the T-Rex is a man-eating machine that spends the rest of its time destroying everything around it.
The most relevant scene was its great escape in San Diego during the second half of Jurassic Park II. Starved and frustrated, the T-Rex roams the streets of San Diego, causing chaos and destruction. At one point, it throws a bus through a Blockbuster Video Store (which turned out to be a metaphor for the chain's future - who knew?).
The signature roar of the T-Rex has become a staple in monster movies ever since. The roars of the Cloverfield monster bring back memories of our days watching disaster unfold in the first Jurassic Park film.