After frustrating millions of video game players by putting pesky Goombas, Buzzy Beetles, Piranha Plants and the fire-spitting dragon Bowser in the path of Super Mario and other animated game characters, Nintendo is trying to put a legal roadblock in front of a rival toy maker that has developed a device to help Super Mario.

Nintendo of America Inc. filed suit in San Francisco yesterday, alleging that Lewis Galoob Toys Inc. is violating Nintendo copyrights by marketing Game Genie, a $50 attachment that allows players to modify Nintendo games in several ways. Nintendo argues that the device creates "derivative" versions of games that are copyrighted by Nintendo.

What's worse -- or better, depending how you look at it -- Game Genie has the ability to make Nintendo games much easier to beat. "Galoob's product directly compromises the depth of play and challenge of Nintendo's games," Howard Lincoln, senior vice president of Redmond, Wash.-based Nintendo, said in a statement.

"Using Game Genie, Nintendo games, which now take hours to master, can be 'mastered' in a matter of minutes, without any skill whatsoever," Lincoln said.

Indeed, Game Genie -- which is due to hit stores in a few weeks -- sounds like a Nintendo junkie's dream.

Attached to the basic Nintendo console, it gives players control over many features of Nintendo games.

With it, users can give their characters infinite "lives," make them impervious to obstacles, help them jump higher and even skip whole game levels to allow the exploration of new worlds.

Awesome, dude.

Game Genie is the first venture into video gaming for South San Francisco-based Galoob, a fast-growing toy maker best known for its Micro Machines miniature cars and several lines of dolls.

Galoob officials say the device does not violate Nintendo's copyright, and they're so confident that they went to court two weeks ago seeking a declaratory judgment that the company has the right to make and sell the Game Genie.

"We're thoroughly convinced that the product doesn't infringe on anybody's rights, including Nintendo's," said Steven M. Klein, executive vice president and general counsel of Galoob. "We believe strongly that they are completely wrong."

Nintendo argues that the advantages provided by Game Genie are similar to those afforded by "speed-up kits" marketed for the Pac-Man arcade games several years ago.

Courts banned those kits after deciding they created derivative versions of Pac-Man.

But Galoob says Game Genie doesn't match that precedent.

"It allows the owner of the game to program in various modifications to how the game is played, and that act is specifically provided for and allowed under the U.S. copyright act," Klein said.

The lawsuit against Galoob is the latest in a series of legal actions that Nintendo has been taking in recent months in an effort to protect its dominant position in the nearly $4 billion U.S. market for home video games.

In March, a federal appeals court in the District, ruling in a case filed by Atari Games Corp., said that Nintendo could sue retailers who sell unauthorized cartridges made by Atari and other manufacturers for Nintendo games.

And earlier this year, the Federal Trade Commission reportedly began an investigation into the possibility that Nintendo's 80 percent share of the home video game business represented an unfair monopoly.