CYPRESS — It took a cyberchicken that hatches from a plastic egg to put Bandai America Inc. back on top of the toy industry food chain.

The Cypress-based company, the U.S. subsidiary of Japanese toy giant Bandai Co., sells the Tamagotchi, the virtual pet that's been flying off store shelves.

Since Tamagotchi's American debut in May, Bandai has sold more than 3 million of the chip-based critters in the United States. The Tamagotchi was the top-selling toy in the nation in May and June, the last month for which figures are available, according to NPD Group, a Port Washington, N.Y., research firm.

Worldwide, more than 12 million Tamagotchis have been sold, and Bandai now believes the figure will hit at least 25 million this year.

"There's no doubt it's a huge hit," said toy consultant Christopher Byrne, editor of Market Focus: Toys magazine.

Bandai officials can scarcely conceal their giddiness over the Tamagotchi's reception in the $22-billion-a-year U.S. toy market.

The company has nine plants around the world churning out the gadgets. With retailers saying they'll take as many as the company can deliver, sales are now "limited by manufacturing, not by demand," said Gene Morra, Bandai America's vice president of marketing.

"The minute they go on the shelves, they don't stay there," said Toys R Us spokeswoman Carol Fuller. "If we could get more, we would be thrilled."

But Bandai, the company behind the Power Rangers toy craze of a few years ago, knows well the fickleness of the toy business. It recently hired a marketing executive director and is planning new versions of its virtual pet in hopes of giving it added shelf life.

Undoubtedly, Bandai stands to earn a barnful of profits from the Tamagotchi this year, analysts say. But in the toy industry, as in the fashion and movie trades, hits fade quickly and companies can plunge from the top of the heap one year to the bottom the next.

"There's no question that having a megahit of this magnitude does wonders for the financial health of the purveyor," said David Leibowitz, managing director of Burnham Securities in New York. The question is how long the good times last, he said. "Novelties, which is the niche area that these products fall under, tend to be short-lived."

Remember Cabbage Patch dolls? Their maker, Coleco Industries Inc., couldn't produce another popular toy and went out of business. So did Worlds of Wonder Inc., the company behind the talking bear Teddy Ruxpin.