In its suit against MariCar, Nintendo accuses the company of using its characters without permission. Kenichi Sugimoto, a spokesman for Nintendo, said that it had previously warned MariCar about using its characters but “did not receive a good-faith answer.”

MariCar said in a statement that it had discussed its services with Nintendo and consulted with legal experts who judged that its business model would not violate Nintendo’s copyright. It also said that it had hoped to work with Nintendo.

It added that traffic related to the lawsuit had overwhelmed its website and communications systems, which it said resulted in an unspecified number of real-life Mario and Luigi wannabes getting temporarily lost in the streets.

“We cannot even imagine how much it would cost in a court dispute against the world-famous company,” the statement said. “We are afraid that our business will be hugely influenced.”

Nintendo has typically kept tight control over both its hardware and software. But the value of Mario, Luigi, Link and the rest of its stable of pixelated players won newfound attention after the Pokémon Go mobile video game became a global hit last year. For that game, Nintendo departed from its traditionally go-it-alone strategy and teamed up with an American start-up to bring its content to small screens, showing it could potentially make money on its famous names in untraditional venues.