New York ? When Lori Fowlkes first saw robotic Zhu Zhu Pets toy hamsters in September, she remembers her kids started jumping up and down and saying “Please! Please! Can we buy them?”

A hamster from Zhu Zhu Pets, by Cepia, is shown Oct. 1 at the Time to Play Holiday 2009 Most Wanted List event in New York. Zhu Zhu Pets, which retail for , are this year’s bona fide must-have toy.

Seeing a fully stocked shelf, she decided to hold off until Christmas.

That was “before I knew that the hamsters would soon be off the shelves and more scarce than an H1N1 vaccine,” said Fowlkes, 32.

Now she can’t find them anywhere.

Zhu Zhu Pets, which retail for about $10, are this year’s bona fide must-have toy, following in the footsteps of past crazes for Tickle Me Elmo and Cabbage Patch Kids. On resale Web sites like eBay and Craigslist, they fetch $40 or more. Vital accessories such as the hamster car and funhouse are sold separately.

By many counts, the toy is an unlikely hit. They’re in a field crowded with toy pets. The hamsters, which scurry around, make noises and drive cars don’t always work the way you expect and have a limited range of action.

“Honestly, I don’t really get it,” said BMO Capital Markets analyst Gerrick Johnson. “But I don’t need to get it for a toy to be hot.”

The toys do have several factors that make them compelling, Johnson said: fun accessories and scarcity — sometimes when something is hard to obtain it makes people want it more. And they have one big thing going for them in tough economic times: They’re cheap.

“The last couple of years the robotic pet has been very popular, but those have been very expensive,” like Hasbro’s $250 robotic dinosaur Kota the Triceratops, he said. “But here’s a version of a robotic pet that only costs $10.”

Hasbro’s line of lower-priced Furreal Friends robotic animals have not hit the same chord, perhaps because they still cost more, are immobile and don’t have any accessories.

Zhu Zhu Pets, aimed at 3- to 10-year-olds, have rushed in to fill the void. But unlike past “It” toys made by large manufacturers like Mattel’s Tickle Me Elmo and Tiger Electronic’s Furby, Zhu Zhu Pets are made by tiny Cepia Inc. of St. Louis, with just 16 employees in the U.S. and 30 in China, making their success even more unlikely.

Creation of a craze

Just six years old, Cepia previously worked on an electronic dispensing device for consumer products before turning to toys and its only other product, a line of light-up bears called Glo-E Bears.

The company was started by toy industry vet Russ Hornsby, 56.

The success of Zhu Zhu Pets wasn’t entirely accidental. After being inspired by classic robotic toys, like the barking puppy dog who flips, Hornsby created a prototype. Stores in Phoenix were used as a test bed in May.

The company got the word out with a savvy mix of local cable ads and parties thrown by “mommy bloggers.”

Hornsby said he was hoping to sell three to four pets per store per week, but was secretly hoping for eight. The result, Hornsby said, was exponentially higher, though he wouldn’t say how much.

“The rate was so astonishing everybody had to go back and pinch themselves,” Hornsby said. Toys R Us pulled all of the test data to make sure it wasn’t being manipulated, Hornsby said.

That gave a running start to Cepia’s national rollout in August.

Ads on cable stations Nickelodeon, Cartoon Network and Disney XD have proved to be catnip to kids.

“My daughter saw a commercial for them on Nickelodeon or one of the kid channels and instantly wanted it,” said Tara Purdy Callender, 21. Her daughter’s 6th birthday is on Nov. 25 and “all she wants is Zhu Zhu pets,” lamented Callender, whose search has been fruitless so far.