PHOENIX — The scout-team stint remains legendary.

Back in 2017, when rookie Patrick Mahomes was serving his one-year apprenticeship behind Alex Smith, the Kansas City Chiefs’ first-round draft pick habitually turned heads with his penchant for freakishly unconventional and hyper-accurate throws. Often, the passes would come against K.C.’s first-team defense, as Mahomes impersonated the upcoming opponent’s quarterback in practice.

“Oh, we saw it every single day,” Chiefs offensive coordinator Eric Bieniemy recalled Monday at Super Bowl Opening Night in advance of Sunday’s showdown between the Chiefs and Philadelphia Eagles.

“When he was taking scout-team reps, you just saw of the magic that you now see on Sundays. There were no-look passes and crazy arm angles and a bunch of things you just don’t normally see on a football field. There were moments where we’d just look at each other and go, ‘Did we just see what we thought we saw?'"

Those moments helped give coach Andy Reid and others in the organization confidence to trade Smith to Washington the following spring. Mahomes also showed flashes of the greatness to come during his preseason performances.

“The moment for me was when we were playing the Titans in the (2017) preseason,” said Chiefs senior offensive assistant/quarterbacks coach Matt Nagy, who was the team’s offensive coordinator at the time. “He scrambled around as the play broke down, right to left. It reminded me of what we saw from him at Texas Tech, with the defense rushing three and dropping eight. Finally, he rolled to his right and threw the ball 60 yards on a dime to Demarcus Robinson. We were on the sideline, just shocked. We looked at one another and said, ‘This is crazy.'"

Mahomes started the regular season finale, after the Chiefs had clinched the AFC West title the previous week, and played well in a victory over the Denver Broncos. In 2018, he began a five-year run of brilliance that has put him on an all-time-great trajectory. On Thursday, he’ll likely win his second league MVP award. On Sunday, he’ll go for his second victory in three Super Bowl appearances. He has started the past five AFC championship games.

At 27, Mahomes is at the top of his profession — and he still blows away his teammates and coaches on a relentless and constant basis.

“It’s wild,” said veteran Chad Henne, Mahomes’ backup. “Coach Reid will put plays in during the week, and Patrick will do something off of it in practice — maybe pitch it back when he’s not supposed to, he and (tight end Travis) Kelce putting their own little nuances on it — and Coach will be like, ‘Let’s do that.’ And I’m thinking, ‘Maybe let’s just run the play you designed?’ But a lot of times Coach Reid will just go with it.

“That’s how we came up with ‘Circle of Death’ and ‘Snow Globe’ and some of those other plays. We have drills to help quarterbacks move in the pocket, and from that Patrick comes up with ‘Ring Around The Rosie,’ and the play is born. It’s crazy. How the hell does that happen?”

It’s a question people inside the Chiefs’ training facility have been asking for nearly six years. And Mahomes’ athletic skills aren’t even his most striking quality.

“It’s not just what he does physically, how he throws the ball, but what he does up here,” said Nagy, pointing to his head. “He could be standing with us now, and there could be four conversations going on around him. And he’d be getting every word and processing it. It’s weird. It’s hard to describe. But it’s cool.

“This kid’s the most competitive human being I’ve ever met in my life. He’s just made different.”