My first time I encountered this, I was with my tribe, me and my tribe thought "oh sweet a rex" next thing I knew we were running into the redwoods, then we were slain by some troodons, never think this thing is a rex, It's a rex on steroids
If one is encountered near water, you can simply lure it out to sea with a flyer and it will swiftly drown. Given the water is deep enough. If encountered inland not near water. Pray to the overseers you have something fast enough to out run it. Then promptly die because they're as fast as a mad Hispanic mother with a shoe. Not as deadly as one though.