They are looking up in horror, their faces contorted, their ears covered to avoid the pain. All this because Hugh Douglas is singing.

	Douglas' killer instinct saved Philly's season.

"I'm a believer!" he bellows from his locker at the Eagles practice facility, doing his rendition of the song from Shrek. Douglas' locker is in the middle of the room, which is perfect, not only because the location guarantees his solos an audience, but because he's the heart of the team -- and because his "Believer!" bit is the anthem for Philadelphia's season.

He wants his teammates to remember that this year -- with a defense that finished the regular season ranked second in the NFL in points allowed -- they're not just the Philadelphia McNabbs. "Hugh's a wonderful teammate," McNabb says. "You just don't want him to sing."

Too late. Douglas is cranked and cannot be uncranked. That's why coach Andy Reid won't ride on the same bus as the pregame-piping defensive end. But his 12.5 sacks (tied for fourth-best in the NFL) make his howling a little more tolerable. In earning his third straight Pro Bowl spot, the eight-year veteran from Central State in Ohio has had his best all-around season. "He's always been a good pass-rusher," says defensive coordinator Jim Johnson. "For him to be a run-stopper, it was just a matter of recognition and leverage. He doesn't get hooked like he used to. He's become more disciplined and alert."

Teammates used to needle Douglas for his freelancing style on the field. His explosive power would slingshot him into backfields, leaving him exposed to draw plays. Now he's become a better tactician than anyone ever expected. After two off-seasons of working out with Shannon Sharpe in Georgia, the 6'2'', 280-pound Douglas has improved his upper-body strength and learned to use his legs as an anchor to fend off blocks and hunt the ball.

But his real improvement has come in the film room. The Eagles spend more time watching game tape as a unit than they do in positional meetings. Johnson expects everyone to make audibles on the field, not just one player. A perfect read includes 11 mouths shouting the same call. So Douglas studied to ensure that his on-field vocals were as clear as his off-field ones. "It was all presnap stuff," he says. "Stances of tackles, if the back makes eye contact with me, if there's motion. I studied it harder than ever."

When McNabb broke his right ankle in Week 11 and the Eagles' season was left to a pair of quarterbacks with 29 combined pass attempts in two years, Douglas started his "I'm a believer!" howls -- and something wonderful happened. The Eagles finished by winning five of six, with the defense giving up just 12.3 points a game and A.J. Feeley's offense generating a respectable 23.8, not far off McNabb's 27.

	Douglas started his "I'm a believer!" howls -- and something wonderful happened.

Johnson didn't blitz as much, but it was because Philly was always ahead. And now that the playoffs are here and McNabb is back, Johnson's quiver is full of arrows. No team in the NFL likes to bring so many blitzes from so many different looks as the Eagles. Defensive tackle Brandon Whiting sat by his locker recently and opened up the game plan against Dallas in Week 16. On one page: 10 blitzes for first and second downs -- run from 10 different formations. On another: 15 nickel-package blitzes with as many different looks.

But none is as scary as when Douglas takes the stage. As the Eagles prepared to play their first McNabb-less game, against San Francisco, Douglas went stir-crazy and started singing. He pulled over a trainer and used the guy's bald spot as a microphone. The locker room blew up laughing. Douglas yelled, "Let's go get these guys!" Philly won in a snooze, 38-17. And Douglas had done what he'd set out to do.

Made believers of 'em all.

This article appears in the January 20 issue of ESPN The Magazine.