Amonkie, according to these articles, the thing you mentioned was in
addition to the giant creature.
Spoiler:
There’s a polar bear that doesn’t seem to belong on the South Pacific island on which the characters are stranded. There also seems to be something Kong-size lurking in the distance, but neither we nor the characters get any kind of real look at it. We just see huge chunks of forest getting stomped down. And Greg Grunberg, who cameos as the crashed plane’s pilot, is viciously snacked upon by something both colossal and unglimpsed.
Here's two links to different reviews and interviews with one of the writers.
They contain spoilers and semi-spoilers.
Also, I would have copy/pasted them here, but they are just too damned long.
You'll just have to excersize your finger.
http://www.aintitcool.com/display.cgi?id=18025
http://www.aintitcool.com/display.cgi?id=18187