DENVER - There are things going on with these Broncos that have never been done before. Things we've never seen before.
Special, fantastical things that defy neck surgeries and NFL record books.
But isn't this the question hovering in the dark reaches of your mind: How do we know That Thing that happened last season won't become a thing again this season?
"It's just a different team," Eagles cornerback Cary Williams told me.
After the Broncos took Chip Kelly's Eagles out to the parking lot, 52-30, at Sports Authority Field on Sunday, I wandered into the Eagles nest. Their locker room was a sad, sad place, green with Manning envy and dim with despair.
That's where Williams was. See, he was a cornerback for the Ravens when they stopped the seemingly unstoppable Broncos on a frigid, forgettable night last January. What's the difference in these Broncos?
"They've been together now two years," Williams said. "They showed it."
I have a theory why this season is different, and it has nothing to do with Peyton Manning's 16 touchdowns (against zero interceptions, tying an NFL record) en route to a 4-0 record.
It has nothing to do with Manning throwing 201 passes without an interception (a career best) or the Broncos' 179 points (four shy of the NFL record through four games), or the Eagles fan in Section 316 who felt so bad by the third quarter, he bought a beer for a Broncos fan.
It has everything to do with what's going on in Kansas City. Yes, in Kansas City.
The 2012 Broncos weren't missing much. Maybe a dome and space heaters on Jan. 12.
But teams that win 11 straight games to close a regular season aren't missing much.
Here's one thing they were missing: A challenger within the division, a rival to force them to lift their game to a playoff level - before the playoffs, because, let's be honest, This Thing is all about the playoffs.
The Chiefs are that challenge, the space heater that will keep the Broncos warm through November and into December. Last season, they didn't have one.
And That Thing happened.
"I'd by lying if I said we didn't notice what they're doing," Broncos defensive tackle Terrance Knighton told me. "I'm pretty sure we want to see Kansas City lose. They want us to lose."
Is it a good thing the Chiefs are 4-0 and the Broncos won't have the same number of wins as the rest of the AFC West combined (13), like last year?
"Definitely. Definitely," Knighton said. "We have our own motivation, our own goals. But we keep an eye on them."
"They always had good players. They just couldn't get it done," Rahim Moore said of the Chiefs. "Now they are."
Let's not go too far, folks. Kansas City would be lucky to stay within a touchdown of the Broncos right now. The Broncos have won 15 straight regular-season games by at least seven points, the second-longest streak in NFL history.
For one, the Broncos have almost as many touchdowns (23) as the Chiefs have punts (26). Whoever beats the Broncos - someone will, right? - must be able to match scores.
"There's still things we can work on," said Wes Welker, a perfect addition to this offense, who caught two of Manning's four touchdown passes.
The Eagles have played both, losing by 10 to the Chiefs and by a gazillion to the Broncos. Who's better?
"Kansas City, to me, was more simple than what this was. They're still trying to jell as a unit," Williams told me.
This is the sixth time the Broncos have opened a season with a 4-0 record. Four times, a Super Bowl happened. The fifth time, Josh McDaniels happened.
Considering the Chiefs' schedule and the Broncos, well, everything, it's quite possible this will happen on Nov.?17 in Denver: "When we play them, we both might be undefeated still. That would make it more interesting," as Knighton said.
What's going on with these Broncos is far more than interesting.
It is special, fantastical, the kind of scoring numbers you see on video games.
"May have to give ol' Thunder an IV after this one," Manning joked of the horse who runs on the field after the Broncos score.
This is A Thing, and it's a great thing for the Broncos there's another thing going on in the AFC West.