Part sci-fi, part horror, all drivel, this schlocky Stephen King adaptation is amusingly dreadful.

Four friends share a common bond: years before, they helped a simple-minded kid who endowed them with precognitive and psychic powers.

Forever connected, Henry (Thomas Jane), Beaver (Jason Lee), Jonesy (Damian Lewis), and Pete (Timothy Olyphant) retreat each year to a woodland lodge, to reminisce, drink beer, and hunt deer.

So far, so "Stand By Me". The childhood flashback scenes have a certain charm, while the adult incarnations are eminently likeable. But then the group's country idyll is interrupted by a bemused stranger, whose flatulence and bulging stomach hint at something dwelling within...

And it's not a nice something.

In fact, with its giant worm countenance and platter of pointy teeth, this "Shit Weasel" is quite unpleasant. And it's not alone...

Not since "From Dusk Till Dawn" switched from gripping thriller to vampire trash has a movie changed tone so violently. Having established its characters, piqued the interest, made us care, "Dreamcatcher" spectacularly self-destructs.

Morgan Freeman pops up as a frothing-at-the-gob colonel; Tom Sizemore his conscience-stricken number two.

An "Independence Day"-style set-piece prompts embarrassment; the alien speaks like a toffy-nosed Brit; the dialogue slides into unbelievable awfulness. (Sample line: "If we don't get after him he'll get out of range, and that's where the shit hits the planetary fan.")

Of the performers, Lee is his usual charismatic chump, and the underrated Olyphant shows he has range. Lewis does what he can with the toughest, silliest role, but can't redeem the script's inherent idiocy.

The mystery is how double Oscar-winner William Goldman ("Butch Cassidy and the Sundance Kid", "All the President's Men") and director/co-writer Lawrence Kasdan ("Body Heat", "Wyatt Earp") created something so risible.

"Dreamcatcher" - wait for it! - is a nightmare.

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Animatrix short "The Final Flight of the Osiris" is being screened before "Dreamcatcher".