New York ? Jeremy Chase admits to shaking down his enemies. His Web site advertises extortion, hits and prostitution for a hefty fee.

Chase is a mob leader — but only in the virtual world. He is one of hundreds of players who found the path of lawlessness and deviance too irresistible when The Sims Online challenged them to “Be Somebody … else.”

The popular commercial game, where thousands of people interact electronically, is turning into a petri dish of anti-social behavior. And that’s raising questions about whether limits on conduct should be set in such emerging virtual worlds, even if they are huge adult playpens.

“Games give people the opportunity to either do something they’ve never had the ability to do before or allow them to do the stuff they are too afraid to do in real life,” said Chase, an unemployed, self-described computer geek who lives in Sacramento, Calif. “This is as close to the real-life mafia that I’m going to be able to get.”

All online games see their share of ne’er-do-wells, or “griefers.” In other games where violence is the norm and killing routine, thugs delight in slaughtering the less powerful and stealing their loot.

But there are no guns in “Sims,” made by Maxis, and it’s impossible to do serious harm to another player. That means griefers — admittedly a small percentage of the game’s 100,000 subscribers — have to be devilishly creative in their social deviance.

Chase and others insist they’re just role-playing like everyone else in the game. But harassment can be a big deal in Sims, which resembles a neighborhood of virtual dollhouses where you build a home and invite others to come over and play.

The game’s raison d’etre is socializing; barely a half year old, it’s the biggest game yet whose rewards come from making friends and being popular.

One mob tactic is gathering the foot-soldiers to stigmatize someone else with several so-called “red links” — a sort of demerit that shows others how many enemies a player has.

Jeremy Chase, co-founder of a group called the Sim Mafia, displays a pair of handcuffs as his Sim character, JC Soprano, on screen in white, pulls the heart from another player, at his home in Sacramento, Calif. Chase and others have started a mafia within the game The Sims Online, in which they go around doing hits on other players. Even online, when players are rewarded for making friends and being popular, some players choose to act in an anti-social way.

For gamers who have spent hours building a reputation, red links can be devastating. The platform may be virtual, but the attack isn’t.

“It’s only a game but the people operating those little animated cartoons are real,” said Holly Shevenock, a postal worker from Harrisburg, Pa.

Shevenock quit playing Sims because she was spending too much time in it — up to five hours a day. “If you’re not careful, you begin to play this game with your real emotions.”

Psychologists who study online behavior say in-game spats and the visceral responses to them aren’t surprising. With simulations becoming more lifelike, the line between real and fake is blurred.

“The more real you try to make these online worlds, the more the problems are real-world problems,” said John Suler, a Rider University professor who specializes in the psychology of cyberspace. “It’s not always easy to contain this stuff in the fantasy world.”