It's time to make a creature. Let's start with its body. Stretch down a pair of legs and pull out two arms so that it looks long and lean. On one end of the body, pop on intelligent eyes behind large round glasses. Add a mop of peppery hair and a prominent nose and ears. Sprinkle on scruffy semibeard growth. Call it Will Wright.

Now put the creature in its habitat: the workspace of a computer game developer in Emeryville, Calif. Spread the studios of Maxis Software, which Wright cofounded in 1987, over the floors of two nondescript office buildings. Sprinkle the interior with dirt-encrusted mountain bikes leaning against cubicle walls and overgrown, pumpkin-orange beanbag chairs. Now surround Wright with others of his kind, hunched behind desks, typing at keyboards, PC monitors glowing.

The software engineers, artists, and others who work at Maxis, now owned by video-game giant Electronic Arts, have migrated here because Wright is a legend. Over the past two decades, the 48-year-old Wright, who studied architecture and mechanical engineering at Louisiana Tech University, has utterly transformed his industry with hits like SimCity , in which players build virtual towns, and the best-selling computer game franchise of all time, The Sims , in which players create virtual people and then watch them interact. In the process, Wright has helped forge a new, more toylike frontier in computer gaming, where the main goal is not so much to score points or kill bad guys but to create cool stuff.

The game they're working on this bright February day is called Spore , and it's the most ridiculously ambitious simulation game yet. Sure, there've been virtual worlds like Second Life , which let you customize your characters. In games like Fable and Black & White , the characters even evolve in appearance and reputation based on how the player defines them: the more evil your beast, for example, the more feared it becomes. LittleBigPlanet , an upcoming game from Media Molecule for Sony's PlayStation 3 game console, is built around player-made terrains and characters. But Wright's Spore is by far the boldest in terms of unleashing players' creativity. In Spore the players create life itself--starting with ooze-dwelling, one-celled creatures that learn, grow, and evolve into intelligent beings with advanced cultures and technologies, able to conquer their planets and outer space.

Computer gamers everywhere have eagerly awaited Wright's latest project since he began talking about it in 2000. Spore is finally due to be released this month, more than a year behind schedule. Wright attributes its recent delays to localization, the process of tailoring the game to different countries and languages. Others around the Maxis office cite the boss's high expectations. Wright concedes their point but shrugs it off.

”For games, it is a long time, but for me it's not a big deal,” he says, sipping coffee in his cluttered corner office. ”I'd rather spend a couple of extra years and have it be a big seller than short it by a year or two and have it be mediocre.”

Spore is anything but. Other games may look and sound better, but few games are as original as this one. It offers players far more choice and open-ended play than any game before it. If Spore lives up to its creator's vision, it will likely be heralded as one of those milestones that redefines what a game can be--just as Doom , a first-person shooter game, pioneered fast-action multiplayer competition in 1993 and Guitar Hero delivered the thrill of music performance by introducing a guitar-shaped controller.