I’ve been watching season one of LOST (pronounced “lahwst”, not “lost” — it’s a common mistake) and because I am only on season one I haven’t been able to listen to other people’s speculations, or voice my own. So I’ll post my theory here, based on about a dozen episodes and the following clues: a metal hatch in the ground; polar bears; a 30-ft high monster that is very heavy and mechanical sounding. Here’s the theory:
The “hatch” leads to an underground habitrail system for the polar bears, who occasionally come out of these hatches and strap on 30-ft high metal exoskeletons which they clomp around in (the “monster” that lurks on the island).
So, even though I’ve sussed it, I’ll keep watching because I need to know why the polar bears would do this.