SANTA CLARA Rivalries so intense they blow out eardrums and melt the paint from stadium walls?
Jim Harbaugh's been around them all his life.
The 49ers coach loves them, feeds off them, thrives amid them, which is perhaps why a little amateur psychiatry here he can't help adding oxygen to the flames.
In 1986, the then-Michigan quarterback piped up and made a guarantee frowned upon by old-guard coach Bo Schembechler that the Wolverines would beat arch rival Ohio State later that week and earn a trip to the Rose Bowl.
Result: Harbaugh threw for 261 yards and Michigan won 26-24.
In 2007, the then-Stanford coach antagonized USC coach Pete Carroll by saying he heard Carroll was leaving USC and later declaring, "We bow to no man. We bow to no program at Stanford University."
The statements were akin to a field mouse poking a grizzly bear with a stick. Stanford had gone 1-11 the previous season and USC was ranked No. 2 when they played in Los Angeles that year.
Result: Stanford won 24-23, even though the Trojans were favored by 41 points.
This week, Harbaugh has done his best to pretend that Sunday's game in Seattle is ho hum just another road trip. He played dumb when asked why former Stanford players-turned-Seahawks Richard Sherman and Doug Baldwin seem to have so much animosity toward him.
"Again, I don't know what you're talking about there," Harbaugh said. "No, I have long and good memories, fond memories of both Richard and Doug when we were teammates."
Harbaugh is acting as if the 49ers-Seahawks firestorm is a media concoction, yet he's the one holding the gas can and burned-out matches.
It was Harbaugh who is said to have honked and mock-saluted the Seahawks team bus after a narrow 49ers win last year at Candlestick Park.
The allegation is ridiculous. Which NFL head coach would toot his horn at a vanquished foe? Well, only one comes to mind.
Even 49ers safety Michael Thomas, who played at Stanford and has been with Harbaugh longer than any player, didn't think it was out of the realm of possibility.
"To be honest, I'm like y'all," Thomas said, a huge smile on his face. "If it is true, I can see coach Harbaugh doing it. But at the same time, I don't know if it's true."
It was Harbaugh who, with little prompting, raised the question of whether the flurry of Adderall-related suspensions among Seahawks players in recent years was actually something more sinister.
"You don't know what it is," he said of positive drug tests. "Even when people say what it is, you don't know that that's what it is."
The comments struck a nerve in Seattle.
Receiver Golden Tate implied he'd like to lower his shoulder into Harbaugh. Cornerback Brandon Browner said he'd like to "put my hands around his neck."
No one gets under an opponent's skin quite like Harbaugh. If the crowd at CenturyLink Field breaks a Guinness record for noise on Sunday, Harbaugh should be handed a certificate for his contributions to the cause.
Why can't Harbaugh resist whipping up the intensity? Because he believes rivalries make your team better and that white-hot-intense ones can make your team great.
"I think it always raises the bar for both teams," Harbaugh said this week.
Harbaugh's 49ers and Carroll's Seahawks have become like two great houses the NFL versions of the Montagues and Capulets. Each is striving to acquire as much wealth and capital as possible to stay ahead of the other, and in so doing each is becoming very powerful.
It's hard to say at this point which franchise will emerge as a dynasty, just as it's hard to predict who will win Sunday. But one result is clear: It's become the best rivalry in the NFL, and all eyes are on the West Coast for the first time in 20 years.
Read Matthew Barrows' blogs and archives at www.sacbee.com/sf49ers and listen for his reports Tuesdays on ESPN Radio 1320.