A voracious and nimble dinosaur-like beast. A big blue alien running for his life. A lush CGI-generated environment whose every leaf and droplet of water shimmers with life. The exclusive clip MTV News' debuted during our live stream chat with James Cameron and the cast of "Avatar" made clear why this 3-D alien sci-fi flick has fanboys so pumped up.

The two-minute clip gives us our closest look yet at the Thanator, a roaring, teeth-gnashing, forest-destroying monster that decides Jake Sully (Sam Worthington) is what's for dinner. And Sully's thinking something like, "Don't let me be eaten on this strange planet Pandora!"

Of course, that's not Sully himself sprinting through the woods. A former Marine, Sully controls his avatar with his mind while he lies far away in a lab. Humans have traveled to this planet to exploit its natural resources. Sully is a scout. And he's anything but safe.

In the clip, Sully dashes with machine gun in hand as the Thanator nips at his heels, busting through bamboo and using talon-like claws to weave quickly through the forest. The brassy score highlights the escape-or-become-a-snack stakes. Sully thinks he's safe when he takes refuge under a tree, turning to unleash a barrage of bullets. The Thanator is not pleased. It yanks away the gun and soon picks Sully up in its jaws.

Thinking fast, Sully unhooks his backpack, runs and leaps into the air, plummeting into a waterfall. He plunges deep into the murky green water before emerging, exhausted and waterlogged, as the Thanator continues to roar at him from far above.

The action is badass, the effects work unparalleled, and all together it's yet another reason to get psyched for the December 18 release of "Avatar."

Check out everything we've got on "Avatar."

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