When the fearsome beastie strides toward the heroine and her response is to gesture scoldingly at him and say, "Shoo!," you know you've found a haven from the usual horror-movie hysterics. "Swamp Thing," now at area theaters, isn't completely successful at banishing the old corkers and stereotypes, but it's a harmless, watchable comic-book thriller, refreshingly suitable for kids of almost any age.

The Thing in question does get an arm lopped off at one point (the point being his shoulder), but it soon grows back, and it was only a leaf off the old stalk, anyway.

Swampie doesn't start out as a thing. He starts out as a diligently tinkering botanist who stumbles upon a way to synthesize "a vegetable cell with an animal nucleus" and thereby devise a race of feisty and fecund Superveggies--"a plant for the 21st century," should there be one. Enter The Bad Guys (led by, of all people, Louis Jourdan), who try to steal the formula. The botanist is doused with it and set afire, and less than a reel later bobs up from the briny as a root that runs amok.

Resemblances to the Incredible Hulk are obvious; the Swamp Thing is an incredible pulp, tormented by his affliction, for all the physical strength that goes with it. He keeps leaping to the rescue of the formidable Adrienne Barbeau, who had arrived at the swamp lab to replace a previous assistant eaten by an alligator, and who never once goes to blithering pieces with Fay Wray screams. This is a new breed of horror heroine; when the bad guys attack, she is quick with her wits and with her fists.

However, "two-fisted" is not the most fitting description, for despite the welcome feminist revisionism in Barbeau's character and performance, the real costars of the movie are her famous breasts, which, though not bared except for one brief sidelong glance, do have a way of dominating a scene. Barbeau has to do a lot of running through the bog, and this is particularly impressive under the circumstances. It isn't being sexist to notice such things. It's merely being alive.

The Thing, meanwhile, is a handsome tower of foam latex containing Dick Durrock, who gives the character not only power but poignance. Writer-director Wes Craven tries to simulate comic-book iconography with lots of old-time movie "wipes" as scene-to-scene transitions (twice, a black "curtain" descends, instead of a fade to black), and this gambit flops with a mighty thud. But there are other touches that work nicely, like the deadpan, naturalistic performance of Reggie Batts as Jude, a little boy in whom Barbeau finds an ally against Jourdan and his thugs.

Unfortunately, the violence is not spectacular enough, nor the final battle between Mr. Thing and a not-very-imaginatively transformed Jourdan (he drinks the formula, too) rousing enough, to make this the kind of picture kids talk about for days after. But at least it's not vicious, or gruesome, or peopled only with hateful creeps.

Thus it's a tad surprising that it apparently didn't occur to the filmmakers to have somebody--Barbeau, perhaps--state, or rather, sing, the obvious: "Swamp Thing, you make my heart sing. You make everything grooo-vy . . . Swamp Thing, I think I luv you. . . ."