Actually, I've got a theory about what's going on that I'm really pulling for. (I am totally unspoiled, btw, so this is not based on any knowledge of what's coming up other than what the cast and producers have said in the media.) I was reading an MSN article on Lost last night and Dom said: "I think the monster itself actually represents what we're all scared of." Which is followed up by the following: "If you call it a monster," Abrams says, "it becomes kind of disposable and silly and it feels kind of irrelevant or gimmicky. But if you have something that represents terror and represents fear and the darkness of this place, that to me is incredibly valuable."
Personally, I like the idea that the mechasaur isn't real at all, but is a manifestation of everyone's fear. You could argue that Pilot Greg (RIP) was about to die of his wounds anyway, so for him the fear was much stronger, hence the being snatched from the cockpit and strung up in a tree. And other than him, no one has actually been hurt by the monster yet. And no one's even seen it, except Locke, who is the only one on the island who's feeling pretty good about everything, which could explain why he survived the encounter.
I really hope that whatever is going on turns out not to have any real world explanation. I'd much prefer one of the "they're dead and this is hell" or "they're inside someone's dream" theories. Because as soon as you try to give a realistic answer for everything, you're instantly going to be confronted with all these crater-sized plot holes and implausibilities that are going to detract from the goodness of the show (see: The X-Files, Alias). Whereas, if this is just an out-and-out fantasy it's much easier to swallow stuff like Locke's miraculous recovery, because the laws of nature as we know them don't necessarily apply. You can get away with a lot more in a fantasy, as long as you remain consistent within your own carefully defined world, and the audience can just sit back and enjoy the ride.
Although Dom voiced another theory in an ET article that I sorta like even better, because it's just so totally Dom: "What we do know is that it is not a dinosaur. We do know it is scary. One of my feelings is that it may not be coming after us. We may have encroached on its territory, or we may have disturbed its babies. My feeling about it is that it is an elephant with a whole bunch of cats attached to it." ::snort::
In other news, it's the first cold day of the year down here (cold for us being 63 degrees), which has me feeling oddly hyper, like when there's a cold front and the cats get all frisky. It makes me want to jump up and make pumpkin soup and chestnut stuffing and cranberry muffins.
* borrowed from cleolinda, because she rocks