Jim McMahon walks into an interview wearing a leather fur-lined jacket over a white T-shirt, red tights, white tennis shoes and black-and-white wraparound sunglasses with polka-dot glass.

With all this, plus a do-it-yourself punk haircut now grown out, he looks more like Sid Vicious than Sid Luckman.

It's a good thing for the Chicago Bears he plays more like Luckman.

For the jacket and tights, there's no explanation. But he has to wear the shades. When he was 6, he tried to untie a knot in a shoelace with a fork. The fork got caught and flew into his right eye. Surgeons were able to restore his vision to 20-200, but he still has a black spot in his iris, which makes him very sensitive to bright light.

There are two important things to know about McMahon, the 6-foot, 26-year-old quarterback who has led the 16-1 Bears within one game of the Super Bowl: He almost always is injured, and he does weird things. Sometimes, the two occur simultaneously.

"If he is crazy, he's a calculated crazy," said backup quarterback Steve Fuller.

McMahon might be the only professional quarterback who says he wishes he could be an offensive lineman. He doesn't just shake hands after touchdowns, he also gives head butts. ("We just got excited one time and butted heads," he said of the origin.) Playing with pain has gained new meaning in Chicago: McMahon endured a couple of games with a broken throwing hand last year, taking a painkilling shot on the sidelines in full view of the television cameras.

"I think I get hurt more because I play hurt," he said this morning before practice at the Atlanta Falcons' training facility in preparation for the NFC championship game against the Los Angeles Rams on Sunday at 12:30 p.m. at Soldier Field.

Last season, he missed the final six games and the playoffs with a lacerated kidney (two Los Angeles Raiders did it) that nearly ended his career. This season, he has had tendinitis in his throwing shoulder, muscle spasms in his back, a stiff neck and an infection in his leg.

The Bears sometimes wonder what life would be like with a healthy quarterback. McMahon says he wonders, too, but, especially this season, there hardly is much to improve upon.

True, he was out three weeks and didn't start in the 38-24 loss to Miami, but what else would one rewrite in the story of this season, considering McMahon now is as healthy as he's ever been?

"I mighta had a few more stats, that's all," he said.

Although the Bears have not lost a game in which he has been a healthy starter in more than two years, it was one of his relief appearances that endeared him to Coach Mike Ditka and the watching world of Thursday Night Football.

It was the third week of this season, and McMahon already had spent two nights in traction in a hospital. He got out in time to appear before local TV cameras at a news conference, where he wore a neck brace. After the cameras left, he tore off the brace and walked out to practice looking as normal as he can look.

But when McMahon developed a strange leg infection in the middle of the week, Ditka decided Fuller would start against the Minnesota Vikings.

Something else certainly went into that decision: McMahon took time from a practice that week to chat with ABC analyst Joe Namath in the stands. Ditka, reporters said, summoned McMahon to his office to talk about it. Word is they talked loudly.

As the Vikings mounted a 17-9 lead, McMahon, who said in an article in the Chicago Tribune that he began to become a brat at the age of 7 months, kept bugging Ditka to let him play. Finally, Ditka did.

McMahon's first, second and eighth plays were touchdown passes, all improvisations on plays Ditka sent into the huddle. The Bears won, 33-24.

McMahon and Ditka are two strong-willed men. Ditka says he doesn't mind a surprise play that goes for a touchdown, but he chews out McMahon when one of his ad-libs goes awry.

"He's the head man, but on the field, I'm in charge," McMahon said. "Sometimes things happen where he gets upset. That's life. I can't apologize for everything I do. I'm out there trying to make a big play. He just doesn't like it to go wrong. I'm the same way. But you've gotta go and take a chance."

Fun facts to know and tell about Jim McMahon:

Unhappy with a haircut last fall, he shaved his head.

He went to Brigham Young, but he's no Mormon. Asked what his favorite impression of the school was, he answered: "Leaving."

He is married to a Mormon, lives in the Chicago suburbs and has two kids.

He has been known to play golf barefoot.

He makes nearly $1 million a year.

He rides around summer training camp in Wisconsin on a red scooter.

He is "one of the stabilizers" of the Bears, says running back Walter Payton. (What does this say about the Bears?)

"I find him refreshing," said Fuller, one of those Bears who doesn't color outside the lines. "He's got a good plan about what he's doing. He really does. He just has fun with the game and isn't afraid to let that flow over into news conferences."

McMahon, who rides scooters and otherwise hangs around with offensive linemen Kurt Becker and Keith Van Horne, actually is harnessed much more in the Bears' offensive system than he would be, say, in San Diego's. Very often, he is simply handing off to Payton.

"We don't try to throw the home-run ball," McMahon said. "We're more of a plug-it-out, ball control team."

If anything, this makes him more effective. None of his statistics are startling (57 percent completions, 15 touchdown passes, 11 interceptions), but they are solid.

He hardly feels shackled. His audibles, often from screens to longer passes, work wonders. In the 21-0 playoff victory over the New York Giants last weekend, his second touchdown pass to Dennis McKinnon was one of his impromptu calls.

"He played an almost flawless game," Ditka said. So what if many of his passes appeared to be underthrown in the stiff wind at Soldier Field?

McMahon, the fifth player selected in the 1982 draft after an all-America career at BYU, wore scuba gloves that day and loved their effect on his passes.

"I threw spirals," he said.

He says he hopes the temperature is "40 below" Sunday, so he can wear his gloves again.

"I'm gonna wear them all summer," said McMahon, looking to finish off his wardrobe. "I'm gonna wear them for the rest of my life."