It’s truly pathetic when a supposed parody of a movie genre turns out to be worse than the bad movies it’s trying to satirize. That’s the case with “Wet Hot American Summer,” a takeoff on flicks like “Meatballs” that’s an excruciating collection of scenes that fall brutally flat, all played and directed so ineptly that there’s virtually no rhythm (or laughs) to the result. Gross, smarmy and mean-spirited beneath its purportedly affable exterior, the picture wastes the talents of Janeane Garofalo, as the director of the camp where the action’s set, and David Hyde Pierce, as a nerdy professor with whom she has a halting romance. Their relationship is intended to be a sweetly oddball pairing of two endearing klutzes, but it’s so clumsily staged that the real stumble these talented performers took involved saying yes to the script in the first place.

This misfire is the work of Michael Showalter and David Wain, members of the group that made the MTV series “The State,” and it features several others guys from that troupe in the cast (including Michael Ian Black, whom some will recognize from his more recent turn as the snotty host of “Spy TV”). Those of us who never saw the television show can only feel gratitude for the omission: if the movie is this dreadful, what must “The State” have been like?

“Summer” is set on the last day of camp in the summer of 1981. There’s the usual collection of horny, drug-addled counselors constantly engaging in sex and getting high, and scads of kids, supposedly their charges, who play them for fools when they aren’t being ignored or mistreated by them. The humor veers from insipid to vulgar to truly nasty, with remarkably little in between. A recurrent bit involving the camp cook, a Vietnam vet who (as a result) is certifiably crazy, is especially obnoxious; to make it worse, Christopher Meloni (of “Law and Order: SVU”) plays the role with a wild-eyed intensity that’s authentically frightening–and terribly unfunny. By the close one wishes that the setting might be revealed as Camp Crystal Lake, so that Jason could show up and systematically dispatch each and every one of these dreadful people.

The movie is also an embarrassment for a couple of other recognizable performers. Paul Rudd is the resident handsome, incredibly vain stud. His scenes appear to be improvised, and prove only that he has no talent for improvisation. Then there’s SNL’s Molly Shannon, as a recently- divorced arts-and-crafts instructor who’s so depressed by the situation she finds herself trapped in that she breaks into tears at the slightest provocation. (The manner in which she ultimately finds “happiness” is just one of the movie’s deliberately sick climaxes.) At last–a character to whom a viewer of this miserable fiasco can emotionally relate: until she escapes her funk, we feel much the same way she does.