LOS ANGELES  For decades, the Walt Disney Company has largely kept Mickey Mouse frozen under glass, fearful that even the tiniest tinkering might tarnish the brand and upend his $5 billion or so in annual merchandise sales. One false move and Disney could have New Coke on its hands.

Now, however, concerned that Mickey has become more of a corporate symbol than a beloved character for recent generations of young people, Disney is taking the risky step of re-imagining him for the future.

The first glimmer of this will be the introduction next year of a new video game, Epic Mickey, in which the formerly squeaky clean character can be cantankerous and cunning, as well as heroic, as he traverses a forbidding wasteland.

And at the same time, in a parallel but separate effort, Disney has quietly embarked on an even larger project to rethink the character’s personality, from the way Mickey walks and talks to the way he appears on the Disney Channel and how children interact with him on the Web  even what his house looks like at Disney World.