The latest worthy successor to the legacy of Sam Raimi’s “Evil Dead” films is “Slither,” an outrageously freakish and funny horror flick in which extra-terrestrial slugs turn people into pustulant zombies. It is not for the squeamish or the slug-fearful.

Written and directed by James Gunn (who wrote 2004’s excellent “Dawn of the Dead” remake), “Slither” has more laughs than chills, but the fact that it often gets both in the same scene is noteworthy. It’s a slimy, high-energy adventure that borrows from — er, pays homage to — countless previous films, yet it whips all those old ingredients into a highly entertaining new dish.

It begins, as do so many of these films, with a mysterious object from space landing in the woods near a quaint little Southern town. This thing shoots a dart into the chest of local man Grant Grant (Michael Rooker), taking over his body and giving him a newfound fondness for raw meat and animal carcasses.

I shan’t spoil the swell surprise of HOW it happens, exactly, but eventually Grant reproduces, in the form of thousands of fast-moving, highly agile slugs, each about the size and shape of a croissant, only instead of being buttery and delicious, they lunge into your mouth and turn you into a monster. Once you are inhabited by one of these slugs, you sort of become Grant, with his memories and feelings, while the original Grant grows ever more mucousy and huge back at his home base.

Meanwhile, Grant’s much-younger wife Starla (Elizabeth Banks) and the town police chief Bill (Nathan Fillion) are searching for Grant since he ambled off into the woods the other day and local livestock started going missing. Once the slugs get loose, Starla, Bill, and others — including the humorously vulgar mayor (Gregg Henry) and a local teenage girl (Tania Saulnier) — must simultaneously a) run for their lives, b) figure out a way to kill Grant and his wriggly offspring, and c) pause occasionally to remark on just how f’ed up the whole situation is.

This is something characters in these movies don’t do often enough. It always struck me as odd that the people in, say, “Nightmare on Elm Street” have no problem accepting that a maniac is killing people in their dreams. There’s usually one line of “What?! That’s crazy talk!,” and then two scenes later they’re completely onboard with it.

Not so in “Slither.” They realize that these horrific events really ARE happening, but that doesn’t mean they accept them as the new norm. Many is the scene of mayhem and gore that ends with some character — usually the wonderful Nathan Fillion (“Serenity”), in that folksy, no-nonsense way of his — staring in disbelief at what has occurred and uttering something pragmatic like, “Well, we’re probably all going to die now.”

It’s a very savvy film, aware of its heritage but not full of winking irony or self-referential jokes. It has some wickedly grotesque makeup and special effects, too, which is a plus for a movie like this. It reaches a point where it does sort of become just another zombie film — and goodness knows we’ve seen enough of those in the past few years — but then it redeems itself with a cluster of undead citizens lurching awkwardly through the streets calling, “Starla!” That, we haven’t had enough of yet.

If James Gunn is going to write and direct more zippy yarns like this one, complete with the fakely portentous musical score and moderately hammy acting, I may one day forgive him for writing the “Scooby-Doo” movies. We’ll need another “Slither,” though. There were two “Scooby-Doos,” after all.

B+ (1 hr., 36 min.; R, a lot of harsh profanity, plenty of sci-fi gore and violence, a little sexuality.)