SEATTLE -- There is Kaepernick Kryptonite, and it was suddenly everywhere Sunday, dressed in blue and neon green.
The Seattle Seahawks defense swarmed Colin Kaepernick, it hit him, it flustered him, and eventually it humbled him completely on the way to an avalanche 29-3 Seattle victory.
Against every other team, the 49ers and Kaepernick have rambled up and down the field with abandon and confidence.
But not Seattle, the team that blew out the 49ers in the second-to-last weekend of 2012 and then again Sunday.
Nobody makes the Kaepernick-Jim Harbaugh 49ers look pedestrian and nervous on offense ... except the Seahawks, who use speed on the outside and a very physical secondary to push around the 49ers.
Nobody else turns Kaepernick into a non-factor.
"We're not going to win games if I play like that," said Kaepernick, who completed only 13 of 28 passes for 127 yards and threw three interceptions and no touchdowns.
"When we got down, you have to try to make plays. There were a couple balls where I tried to force in there, try to get something going."
And, most significantly, nobody has defeated the Harbaugh 49ers twice in a row ... except Pete Carroll's Seattle Seahawks.
There is clearly a problem here for the 49ers -- they struggle against Seattle generally and they really struggle when they play the Seahawks in the deafening din of CenturyLink Stadium.
The bad part for the 49ers is that their offense keeps getting smashed by the Seahawks -- can't run, can't protect the QB, can't get their receivers loose.
And the really bad part for the 49ers is that it's getting worse each time.
With the exception of some strong defense early against the Seahawks, the whole 49ers team got bullied Sunday and needed the quarterback to save them.
He didn't. And the 49ers got demolished.
"Well, certainly not proud of the way we played tonight, or coached," Harbaugh said. "Wasn't our finest hour."
In last year's loss up here, Kaepernick was 19 for 36 for 244 yards with a touchdown and an interception -- a 72 quarterback rating, which, until Sunday, was the lowest rating of his starting career.
On Sunday, Kaepernick, with a career-worst three interceptions, had a 20.1 rating. The truth is, the 49ers needed a massive game out of Kaepernick, and they didn't get anything close.
Kaepernick threw a key interception in the first quarter at the Seattle goal line on a tipped ball he tried to force into Vernon Davis, and Kaepernick looked skittery throughout.
Many other things went wrong, and Kaepernick certainly wasn't the only problem or close to the worst performer.
But Kaepernick looked more scattered and flustered than he ever has as an NFL starter, and it was right from the start, as the 49ers went to a no-huddle offense and tried to race to an early lead.
"I don't think any of us are real proud of our performance tonight," Harbaugh said when asked about Kaepernick's performance in particular.
Is Seattle, which also played the 49ers tough in a close 49ers victory at Candlestick last year, a problem for the 49ers?
Are the Seahawks -- who come to Candlestick in December for the rematch -- the one team the 49ers can't figure out?
"They're a good football team," Harbaugh said. "I give them a lot of credit, they played very well tonight."
The 49ers struggled before the hourlong weather delay in the first quarter and even more afterward.
Kaepernick was under constant pressure, couldn't get it to Anquan Boldin, who caught 13 passes in Week 1 but only one on Sunday.
"There were a couple times we did some things -- just stalled," said Kaepernick, who also lost a fumble on a blindside sack. "I don't think it was something they did, we just didn't perform.
"We didn't make plays like we normally do."
Meanwhile, Frank Gore was getting completely stuffed -- he gained only 16 yards on nine carries.
So in Kaepernick's QB tenure, the 49ers have destroyed Green Bay twice, beat up New England, gone up and down the field on Atlanta in the NFC Championship game, and run up 468 total yards even in the Super Bowl loss to Baltimore last February.
And they are 0-2 against the Seahawks, scoring a total of 16 points in the two games.
Why do the 49ers struggle so much specifically and only against Seattle?
"We did not play nearly good enough -- facts are stubborn things," Harbaugh said. "That's what took place."
Of course, the 49ers lost 42-13 up here last year and still went to the Super Bowl a few weeks later.
Is that what Harbaugh told this team after this game?
"Gotta bounce back -- we've got to bounce back in a big way," Harbaugh said.
They don't play Seattle for a while, so the 49ers have plenty of chances to bounce back. And to get ready for their next game against Seattle, which is the one team that has humbled the 49ers.
Which makes all the difference.
Contact Tim Kawakami at firstname.lastname@example.org.