It belches, breaks wind and may take over the world.

A $100 robot that belches and passes wind on command has become one of the hottest-selling toys for the holiday season, with more than a million unit sales for Hong Kong-based maker Wow Wee Ltd.

Wow Wee has sold 1.5 million Robosapiens since the toy was introduced in April, two-thirds since September, said Mark Tilden, 43, the robot's creator and a former scientist at the U.S. government's Los Alamos laboratory. Factories in China's southern province of Guangdong are running flat out making as many as 20,000 units a day, he said in an interview.

"It's doing fabulously well," said Pieter Schats, regional managing director for Toys 'R' Us Asia Ltd., a unit of closely held Li & Fung Retailing Group that operates the franchise from Toys 'R' Us Inc. "We reckon it will be one of our top five products this Christmas."

Holiday demand for the robot and thousands of other gifts is boosting production in Chinese factories, whose low wage costs have drawn companies including Mattel Inc. and Hasbro Inc., the world's largest toymakers. China made more than three-quarters of the toys, games and sports equipment shipped to the U.S. last year.

Robosapien, which features 67 pre-programmed functions, was named Toy of the Year by London toy shop Hamleys.

Kasey the Kinderbot

The robot is virtually without competition, Tilden said. Sony Corp.'s $1,900 AIBO dog, which can fetch a bone and whose behavior evolves as it grows older, has shipped 140,000 units since the electronic pet debuted in 1999, according to the Tokyo-based company.

Other robotic toys, such as the $40 Kasey the Kinderbot from Mattel unit Fisher-Price or Hasbro's Transformers Energon Mega Supreme Robot, are aimed at younger children or have few automated functions.

Mattel spokeswoman Jules Andres declined to comment on what the El Segundo-based company may be developing, saying the information is "proprietary." Wayne Charness, spokesman for Hasbro, based in Pawtucket, R.I., didn't immediately respond to an email seeking comment.

Mark Ng, a project manager at Wow Wee, said the company originally expected to sell between 500,000 and 600,000 Robosapiens this year--a level that would start yielding a profit. It aims to sell another 1.5 million units by the end of 2005, he said in an interview on Dec. 10.

The robot, whose torso lurches from side to side as it walks on oversize feet, is controlled by a 21-button remote control and can dance, make karate-like chopping motions as well as pick up things with its three-pronged claws. It will run about 20 hours on a standard battery.

While the Robosapien doesn't speak any language, Tilden and his team of engineers endowed it with noises such as breaking wind, belching and grunting in an attempt to make it span language barriers and appeal to kids and adults alike.

"That turned out to work amazingly well for us," Tilden said. "Because it turns out that a burp is universal."

Tilden, who works as a consultant for Wow Wee, said the Robosapien traces is roots back to 1988, when he started working on techniques to make robots more advanced without billion-dollar investments.

At the time, technological developments had "essentially stalled" and 1960s-era promises that robots would perform many human functions by the end of the century were coming undone, he said.

"The Japanese spent half a billion dollars for a life-size humanoid robot that one day may be able to clean your toilet," Tilden said. "For half a billion dollars I'm pretty certain I could hire Bill Gates as my pool boy," be added, referring to Microsoft Corp.'s chairman.

Tilden worked for the Los Alamos National Laboratory in New Mexico in the 1990s, a stint that included work for government agencies including the National Aeronautics and Space Administration.

What sets the Robosapien apart from other robots, Tilden said, is that its movements and responses are modeled on those found in humans and animals--employing so-called biomorphic robotics--rather than digital technology. Among other things, that helps lower power consumption.

So far, Wow Wee's bet is working. The robot is selling out in markets including Germany, the U.K. and the U.S., said Tilden. The only market where consumers have shunned the Robosapien is Japan, home to Sony, he added.

"It's at the premium end of the price point, but for what you get it's great value," said Schats of Toys 'R' Us. "It's very, very unique and obviously appeals to dad as well."