larson, you step back in time. >> so this is one of the very coolest things. this is the skull of this t-rex, the murray text. >> as in tyrannosaurus rex an 8-ton, more than of 6 million-year-old fossil he has collected. when you find a skull what is that? >> like eecstasy. it's pure joy. >> reporter: he can't contain it. >> back here we have more interesting things to look at, the outside of a vertebrae, filled with pieces of skin. before we go, this is really cool. this is a big dinosaur. this is one of the biggest. >> reporter: as we talk about murray, it's another name that he keeps mentioning. >> this is pretty much sue's size and sue's age, very, very old. >> reporter: does everything come down to sue in your life in. >> i think so. there's sort of a before sue and after sue sort of thing, so i guess you might say that. >> reporter: sue, the single