Twice in the last four years, a team coached by Kyle Shanahan has entered the fourth quarter of a Super Bowl with a double-digit lead. 

While the 40-year-old San Francisco 49ers head coach has plenty of time to rewrite his career narrative, the fact that he still has zero Super Bowl rings is damning.

The Atlanta Falcons wouldn't have blown a 25-point lead to the New England Patriots in Super Bowl LI if not for Shanahan's astonishingly bad play-calling as Atlanta's offensive coordinator, and the 49ers might have held on to beat the Kansas City Chiefs in Super Bowl LIV on Sunday night if not for another dose of highly questionable play-calling from the third-year head coach. 

Sunday's 31-20 loss solidifies Shanahan's reputation as a choker. 

He wasn't responsible for defensive lapses against the Patriots on that fateful night in February 2017, and his defensive coordinator (Robert Saleh) and defensive personnel deserve a share of the blame for Sunday's collapse, but his teams have unbelievably and inexcusably been outscored 46-0 in the fourth quarter/overtime in his two Super Bowl appearances. 

That'll haunt him. It'll stick with him. It'll follow him around for the remainder of his career, no matter how much success he has in San Francisco and/or elsewhere. 

It's clear that with the Vince Lombardi Trophy within reach, Shanahan gets the yips. 

We saw that when he inexplicably called three passes on a late-third-quarter three-and-out that gave the Patriots momentum in a 28-9 game. And we saw it again when he got too fancy and ditched the run in field-goal range while holding an eight-point lead in the final minutes of that game—a puzzling approach that led to a sack, a penalty and a punt that kept the Pats alive. 

And while this Sunday's meltdown wasn't as dramatic, Shanahan again appeared to get in his own head when his team had a chance to put a championship away. 

When San Francisco's Tarvarius Moore intercepted a deflected Patrick Mahomes pass with 11:57 remaining in the fourth quarter, this game should have been over. The 49ers had the ball, a 10-point lead and a running game that looked unstoppable. 

To that point, 49ers running backs Raheem Mostert and Tevin Coleman, as well as wide receiver Deebo Samuel, had averaged 6.9 yards per rushing attempt. Both Mostert and Coleman had already put together monster playoff performances this year, and San Francisco had the NFC's No. 1 running game during the regular season. 

And yet, the 49ers ran the ball just four times the remainder of the night. 

When Mostert gained just one yard on a first-down play with about 10 minutes remaining, Shanahan appeared to panic. Quarterback Jimmy Garoppolo (who did seemingly audible at the line of scrimmage) threw a wildly inaccurate incomplete play-action pass on second down, which led to a penalty, a short scramble and a punt. 

Kansas City then drove down the field to cut the lead to three. And after Mostert ran for a solid five yards on the first play of San Francisco's next series, Garoppolo again threw an incomplete play-action pass, this time out of the shotgun. He threw incomplete under pressure on an obvious passing down after that, and the 49ers had to punt after taking just 48 seconds off the clock. 

Just 154 seconds later, the lead was gone and the script was flipped. 

Shanahan has to at least be considered the worst clock-bleeder in Super Bowl history. 

Sure, the Chiefs keyed on the run. But the box was by no means stacked on that second-down throw just inside the 10-minute mark, and the throw on 3rd-and-5 on the three-and-out came against a six-man box. 

Plus, San Francisco's only two runs in the final 10 minutes gained 22 yards, so it's not as though the running game was no longer effective when called upon. 

Shanahan coached scared with the lead, and he panicked again when he lost it. 

Mostert gained 17 yards on the first play from scrimmage after the 49ers had fallen behind 24-20, but that was the breakout star's final touch of the game. They took a false start penalty on an attempted run right after that, but they threw on 1st-and-15 when the two-minute warning hit. They ignored a wide-open box and threw again on first down at the Kansas City 49-yard line. They threw from the shotgun against a six-man box on second down, and beyond that the hole was too deep.

On that particular drive, the Chiefs—now in the lead—were giving the San Francisco offense openings to run again, and the clock was a non-factor when the 49ers hit Kansas City's side of the field with just under two minutes remaining and three timeouts in their back pocket. 

Instead, they played into Kansas City's hands by consistently putting the ball in Garoppolo's. 

And it has to pain 49ers fans that it might not have come to that if Shanahan hadn't handled the end of the first half in such idiotic and cowardly fashion.

The game was tied 10-10 at that point, and it looked like the 49ers would have a chance to take the lead going into halftime when they made a third-down stop at the Kansas City 49-yard line with 1:45 remaining. But Shanahan inexplicably opted not to use a timeout before Kansas City's punt, costing his team 40 seconds. With less than a minute remaining, they then handed off twice in a row.

They finally moved the ball through the air on third down, but only after the Chiefs forced them to by using a defensive timeout. If not for a tough George Kittle offensive pass interference penalty on the ensuing first-down play, they would have moved into field-goal range. But after that, there was no time to work with, and they had to settle for a halftime tie. 

It's beyond baffling that Shanahan was apparently content with that, especially with such a glaring opportunity to grab critical pre-halftime points. But that again is an indication that he coached this Super Bowl with three-year-old trauma clouding his judgment. 

That trauma is worse now, and it'll likely linger for decades to come. 

Brad Gagnon has covered the NFL for Bleacher Report since 2012. Follow him on Twitter. Or don't. It's entirely your choice.