Call it animal magnetism. While the members of the Academy were busy considering 1993's Great Art, moviegoers went out and voted with their wallets for a very unlikely winner. Ace Ventura: Pet Detective, Warner's comedy about an elastic-faced, Gumby-limbed, Dippity-Do-haired PI, has grossed $37.7 million in its first three weeks, and Hollywood's stupefied power elite is stampeding to woo the film's star and cowriter, Jim Carrey, 32, the comedian who found a mass audience for his explosive brand of physical comedy on Fox's In Living Color. ''The floodgates have opened,'' says Carrey, laughing. ''We're going nuts with offers. I feel like Macaulay Culkin. I just need a good tutor.'' ''In the flavor-of-the-week category,'' adds Ace director-cowriter Tom Shadyac, ''Jim and I now have our head shots in the hall of shame.'' Ace Ventura, made for $15 million, was drafted as a less loopy comedy before Carrey reworked the script with Shadyac, a rookie director who, like Carrey, has been a stand-up comic. ''I've done parts in films before (Once Bitten; Earth Girls Are Easy),'' Carrey explains, ''and I got tired of hearing people ask, 'How come you're not the guy you are on stage?' So we tried to capture that.'' During production, he and Shadyac worried that they had gone over the top. ''Every night we'd go, 'Oh, man, this is either gonna be big or the end of us both,''' Carrey recalls. In fact, almost everybody involved admits to surprise at the magnitude of Ace's success. During Ace's first weekend, says Carrey's agent, United Talent's Nick Stevens, he received calls from ''almost all the studios, and most of the larger production companies that deal in comedies.'' And New Line Cinema, which this August will release Carrey's next film, the special- effects-laden The Mask, is ''excited as hell,'' according to Chris Pula, president of theatrical marketing. ''Jim had a loyal following (from) In Living Color, but now he's recognized as a movie star.'' However, Carrey is still committed to television-for now. He plans to stay with In Living Color at least halfway through next season. Beyond that, he says, it ''depends on what else is going on.'' There's likely to be plenty. As a meek bank clerk-turned-superhero in The Mask, ''not only has Jim achieved a personal goal by becoming a human cartoon,'' says director Chuck Russell, ''but he also gets to do a much subtler, charming form of comedy that an audience hasn't seen from him.'' After that, Carrey-whose asking price is now reportedly in the neighborhood of $3 million per picture-will weigh offers from New Line, Disney, and producer Joel Silver, as well as an Ace sequel (Deuce Ventura?), which could open in summer 1995. ''We'll take Ace on safari,'' riffs Carrey. ''Have him with bushmen talking bushmen language: 'Gling, gling, gling.' And they're gonna kill him if he doesn't teach them how to do the hairstyle. I have the ability to be normal,'' he adds. ''But that's not what people expect of me right now.'' And besides, it doesn't pay nearly as well.