Some players give themselves the ability to magically see and shoot through walls. Others find a way to fly, making them nearly impossible to defeat.
Cheating like this in video games has a long and even respected tradition. Games have often slyly included ways — intentionally or not — for sophisticated players to hack into the software and then skip levels or take on supernatural powers.
But these days, the subject is getting a more serious look. Unlike older games, today's are networked to be played with strangers over the Internet. And now, real money is at stake.
Fantasy games like "World of Warcraft" and computer environs like "Second Life," to name a few, have their own currency or other virtual valuables that can be traded for hard U.S. dollars.
In other words, hacking into a video game to cheat can be a business strategy. And so clamping down on it could be key to maintaining virtual worlds' economies and reputations. Even chip-maker Intel Corp. is suggesting a technology for doing it.
But one huge question is: Can cheating really be stifled?
"What I've always said is: It'll go away the same time crime goes away," said Tony Ray, founder of Even Balance Inc., which makes cheating-detection software called Punkbuster. "There's always somebody trying to get around the rules."
Perhaps, but Gary McGraw and Greg Hoglund, authors of the new book "Exploiting Online Games," argue that video game makers could do much more to stop it. McGraw and Hoglund contend that poor software design enables the vast majority of cheats.
Complex games operate partly on central servers run by the game companies and partly on a player's own computer.
Essentially, the individual computer reports back to the game on the mouse clicks or trigger pulls performed by the player, and the game registers the appropriate response.
That's where cheating hacks often occur: Tell your computer to report 100 trigger pulls for every one actually made, and you've turned a pistol into a machine gun that racks up points much faster.
McGraw and Hoglund offer ideas for how game makers could seal up such holes. And they argue that the entire software industry needs to be watching, since these massively multiplayer online role-playing games are at the leading edge of computing.
"The kinds of problems that they are facing right now are direct indications of the kinds of software security problems we can all face in the coming years," McGraw said.
Cheating tools flourish online, catering to insiders conversant in the games' arcane language.
"Take advantage of this programming breakthrough — why waste time grinding with the grunts.... play WoW in GOD MODE!" reads one ad for a $25 downloadable cheat package for "World of Warcraft" that purports to be "undetectable."
Most online game companies appear resigned to the fact that cheating will occur, so they try to block it by observing game play and looking for suspicious things, like avatars unexpectedly teleporting.
In one incident that could serve as a test case, Linden Lab, creator of the virtual universe "Second Life," ejected a Pennsylvania lawyer and confiscated his virtual property after accusing him of cheating its land-auction process. The lawyer is suing Linden Lab in federal court for $8,000 in restitution.
Nexon America Inc. employs a team of workers who actively look for cheating in its games, including "KartRider" and "MapleStory." They apply patches to fix problems as they arise.
"It's a daily battle that ultimately we have to win," said Nexon's director of operations, Min Kim. "It's just the cost of doing business at this point."
"World of Warcraft" creator Blizzard Entertainment deploys a software program called the Warden to detect cheating and ban perpetrators, but wouldn't agree to an interview to talk about it.
The Punkbuster software works on many first-person shooters and is still being used in new games, like "Enemy Territory: Quake Wars," in which players shoot their way through combat missions.
One problem is that these observer programs are invasive, since they must access the underlying operating system in a player's PC in order to sniff nefarious code. McGraw believes the Warden might even violate California's anti-spyware law.
Sometimes, there appears to be financial incentive for the game makers to be good — but not terrific — at stopping cheating.
Consider this: Cheaters who get banned from games often immediately sign back up under a different user name, paying money for a new account in hopes of trying again. If cheating protections were significantly stronger, fewer perpetrators would continue to buy accounts.
Game companies might have better luck relying on reports of suspicious activity from legitimate players.
One issue that irks aficionados is "gold farming," whereby people pay real money to companies like IGE.com in order to buy in-game currency.
A recent check showed a "World of Warcraft" player could pay $420 to get 6,000 pieces of gold — enough to buy one of the game's pricey flying mounts. Other players have to laboriously work their way up to such achievements.
Buying gold breaks the game's terms of service — and it degrades the overall experience for everyone, said Hubert Thieblot, who leads Curse, one of the largest teams in "World of Warcraft."
A cheating player who takes all the targets in a certain area, for example, leaves too few for everyone else.
"You change your experience with how you play and how you behave," Thieblot said. "If you just buy gold you aren't going to do extra quests, you're not exploring areas as they want you to."
Although Intel's anti-cheating idea is still in the research phase, it could aid people like Thieblot.
Intel's technology would embed a module in a PC's circuitry that would analyze data coming off the keyboard and the mouse and compare it to what a game actually processes.
If there are conflicts — the player clicked the mouse just once but the game read that as "fire 100 shots" — the Intel system would be able to signal the game makers or other players.
The system could also put a "trusted" stamp on seemingly legitimate players.
Intel says its system would not degrade PC performance or be noticeable in game play, but the concept still needs work. Notably, it would require the support of PC makers as well as the game companies that would have to build in ties to the Intel system.
Meanwhile, Starr Long, who with industry veteran Richard Garriott is wrapping up the online sci-fi game "Tabula Rasa" for NCsoft Corp., worries that cheating can now ruin entire game worlds.
Like other game makers, Long won't get into specifics, but says his programmers have done all they can to thwart cheating in "Tabula Rasa."
"In the old days we didn't really think through what would happen once we started letting people play together," Long said.
Now, Long says, "every single piece of content we put in the game, the first thing we say is 'Here's what we want this thing to do.' And the second thing we say is, 'OK, how are players going to try to exploit this?'"