The horrific possibilities of a pumped-up Jim Bowen mutating into a giant squid-like alien with razor-sharp tentacles and NHS dentistry are too grim to contemplate.

But director James Gunn has realised this stomach-emptying proposition with a salivating relish and sicked up a gleeful homage to the classic B-movies of yesteryear.

Oafish businessman Grant Grant (Rooker) - a deadringer for a pumped-up version of the Bullseye host - is in the woods for a bit of slap'n'tickle with local tart Brenda (Brenda James) when he spots something.

Before you can say Zombie Flesheaters, he's been spiked, ironically enough, by a toxic dart fired by an oversized maggot which has just landed courtesy of a blazing meteor.

Initially oblivious to his parasitic little pal, Grant is soon shoving mucus-drenched feelers into Brenda's tummy and she is growing ever-larger on a diet of raccoon and possum in a shed on the edge of town.

Grant's clued-up wife Starla (Banks) figures something is up (he cleans out the meat counter at the local store and dumps it in the cellar)... but it's only when he sprouts tentacles and develops a severe lopsided grin that she realises hubby is not like other men.

Hooking up with college sweetheart and local cop Bill Pardy (Serenity's Fillion), they catch him tucking into a cow and track him to Brenda - now of Mrs Creosote proportions - who promptly explodes, showering everyone with vicious little red slugs.

Soon the squirming critters - having jumped down a few accommodating throats - have turned their hosts into bloodthirsty zombies and switched their attention to Starla and Bill. Who look worried.

Expertly blending humour with horror, Gunn has come up with the Vegetarian Society's worst nightmare - an unashamed rehash of the goriest bits of Romero's finest moments with a major nod to Cronenberg's 1975 feature debut Shivers.

The script bristles with snappy one-liners - "there ain't many places he can hide, looks like a damn squid. Sea World, maybe..." - and they're knowingly delivered by a cast who are only too aware what they've signed up for.

It's a stonking ride made all the more enjoyable with the knowledge that sfx boffins constructed the parasites from therma gel - a staple of the "adult novelty industry" - and the production swallowed up 300 gallons of methylcellulose slime. Nice.

Following in the footsteps of Starship Troopers and Eight Legged Freaks, its good-natured plundering of horror glories past occasionally prompts the sort of nervous laughter you hear in a cinema when what's up on screen is too scary to watch.

This is one that will worm its way into your affections.

Tim Evans