Alien beings destined to inhabit the "Spore" computer game after its launch later this year came to virtual life on Wednesday with the debut of a free "creature creator."

Electronic Arts-owned Maxis has the software available at www.spore.com to let people make inhabitants for an eagerly-anticipated computer game that is the brainchild of "Sims" creator Will Wright.

"Spore," to be released in September, will let people dictate the genetic development of animated characters in a mock universe.

"You are given this God-like power," Wright told AFP in a recent interview at his Maxis office in Emeryville, California.

"You can create ecosystems, biospheres ... We try to make it real science. You can turn a beautiful world into a hell-hole, but you are trying to do the opposite."

Players start as microscopic life forms competing for survival in primordial ooze and work their way onto land, where they evolve into creatures that build civilizations and rocket into space.

Creatures can be made to have scales, fins, wings, claws, extra appendages, additional eyes, or body parts in unexpected places.

The online game's programming gives characters artificial intelligence and figures out how they should walk, laugh, dance, fight or do other things based on what they look like.

Creatures pass on virtual genes to their progeny and build civilizations with cities, governments and economies.

Determined players can go from being an amoeba to exploring space in about six hours, according to Wright. The self-described science fiction fan wove cliches from the genre's popular films and stories into the game.

In a computer game first, "Spore" worlds will be inhabited by aliens made by players instead of professional videogame programmers.

Maxis engineers then animate the creations and use them to populate individual worlds customized for each player.

"So, each player is in a solo game with content evolving and expanding based on what everyone else is making," Wright said. "The game is linear. You eat. You fight. And, eventually you have to mate."

Players can add their creations to an inline "Sporepedia" to share with others and record videos of their aliens in action and upload them to YouTube.

Wright designed "Spore" so each person plays alone in their own world rather than against one another in a shared online universe.