CLERK ROBERT WALLER WAS working the late shift at the Wal-Mart in Fredericton, N. B., when Elmo-mania hit him. Literally. It was after midnight on Dec. 14, and a crowd of about 300 had gathered to get their hands on the store's latest shipment of Tickle Me Elmo, that vibrating, giggling, must-have toy of the holiday season. Waller, 27, was holding an Elmo when the crowd spotted him—and stampeded. "I was pulled under, trampled—the crotch was yanked out of my brand-new jeans," says Waller, who suffered a pulled hamstring, injuries to his back, jaw and knee, a broken rib and a concussion. "I was kicked with a white Adidas before I became unconscious."

That kind of blood lust—not seen in toy departments since the Mighty Morphin Power Rangers craze—is enough to make the real-life Elmo, Sesame Street's sweet-natured, red-furred thingamajig, even redder. "Elmo is so positive about life," says Elmo's puppeteer Kevin Clash, 36, who, more than anyone else, has had a hand in the giggly creature's success for the past 12 years. "He's a cute little monster." Adds Rosie O'Donnell, who helped spark Elmo-fever by featuring him on her show and whose son, Parker, 2, owns the doll (though he dropped the first one in the toilet): "Elmo has all the innocence of a 2-year-old. He wants to take love and give love with that purity."

Undeterred by that message, scalpers continue to advertise their Tickle Me Elmos—the brainchild of a team of Tyco inventors—in newspapers and on the Internet, asking as much as $1,500 at year's end, though Elmo retails for a mere $28.99. "I bought it for my nephew, but with the high demand I decided to sell," says Clarence Howard, 28, who unloaded his Elmo for $100 on Christmas Eve. "Bills have to be paid."

One Springfield, 111., radio station even sent a parachutist down in 4°F weather on Dec. 19 with Elmo strapped to his chest; the first person to grab Elmo—in this case, Pete Stoll, 37, an athletic trainer—took him home. "It's amazing—all over a stupid doll," said Stoll, who plans to put Elmo on display in his house. "But look at me."

Though not everyone is thrilled with Elmo's success—"It's getting sick now," says New York City toy industry analyst Gary Jacobson—Clash, a puppeteer since his childhood, is living his dream. "I wasn't into sports. I was into building puppets," he recalls. "The kids would say, 'Oh, yeah, you sleep with your puppets.' The neighbors would say to my mother, 'Gladys, you should make that boy get out and play' "

Of course, with Elmo voted most popular Muppet by the readers of Sesame Street Parents magazine (Eat your heart out, Grover!) and a new movie—working title, Elmo in Grouchland—on the way, don't be surprised if Clash, who lives outside of Baltimore with his wife, Genia, an RN, and daughter Shannon, 4, should, ever so slightly, develop an attitude. "I'm Elmo, damn it!" he jokes. "I'd like to use that line to get into a restaurant."