In 2016, when Sonny Dykes was in his last year as the head coach at Cal, he and his offensive coordinator, Jake Spavital, found themselves looking for plays to run on 2-point conversions. To figure one out, they used a method available to anyone.

“You know how it is,” Dykes told SB Nation Saturday night. “Everybody’s got the 2-point plays that they run, so we Googled it.”

One of the first plays they came across was a bit of deception Alabama used against Auburn in the 2011 Iron Bowl.

The Tide motioned a massive offensive tackle to the right slot, where he stood on the line of scrimmage, giving Bama seven men on the line, in accordance with the rules. A tight end who’d been hiding next to the tackle on the other side of the formation — and was now on the end of the line — was eligible.

Watch the lineman who slips free to the right and pretends to be catching a pass that’s never thrown, while the ball goes to a guy who’d lined up at left tackle:

NCAA (and NFL) rules require an offense to have seven men on the line of scrimmage at the snap. Of those, the only eligible receivers are the ones on the ends of the lines.

Auburn was understandably confused about who could do what. An Alabama tight end who looked like an offensive tackle slipped free for the easiest 2-point conversion in the world.

Dykes’ Cal team installed the play and practiced it a few times per week, just to “have it in your back pocket,” he said.

During an OT win against Oregon, the Bears deployed it. They motioned a big tackle over to the slot, where he set up on the line. Oregon mistook a tight end who’d been hiding to the tackle’s left for a tackle himself, and the newly eligible tight end slipped free for a wide-open conversion while No. 75 made a show of calling for the ball:

Again: seven men on the line, the lineman as a decoy, and a sneakily eligible tight end catching an easy score after the defense didn’t realize he was even allowed to catch a pass.

On Saturday, Dykes’ SMU Mustangs beat Navy with the same play.

It was overtime. Dykes didn’t want to go back on defense. A rash of injuries would’ve left SMU using two true freshman linebackers on the next series against Navy’s triple option.

So coordinator Rhett Lashlee dialed up the play Dykes had Googled in Berkeley. It worked again:

Lineman Chad Pursley moved from a tackle spot on the left side of the formation to a spot in the slot. Tight end Hunter Thedford became an eligible receiver with no one outside of him on the end of the line, and QB Ben Hicks threw him the winning pass, even though Navy wasn’t all that fooled.

A lot has to work. The first thing is to not break any rules, which required a lot of careful work by SMU.

The pre-snap shift to the slot by a big lineman is important. The offense could just start him there, and maybe it’d work, but the shift helps disguise the tight end on the other side of the formation. It makes it likelier the defense will forget to cover that guy, who wasn’t an eligible receiver before the big dude shifted away from him.

The NCAA’s rulebook locks in offensive linemen wearing Nos. 50-79 as ineligible receivers — “restricted linemen” — when they put their hands below their knees. So SMU had to make sure the motioning lineman, No. 57 Pursley, didn’t do that, but that Thedford, the tight end wearing No. 88, did, so he’d look like a tackle.

“There’s some things that you have to follow, some protocol,” Dykes said. “You just want it to look like that guy’s not eligible, so you move the tackle over.”

The big lineman who goes in motion also has to resettle on the line of scrimmage. That ensures the offense has seven men on the line and avoids an illegal formation flag. That player’s considered on the line as long as his head is parallel to the waistline of the snapper. SMU’s Pursley (the red No. 6 here) appeared to do that, but might’ve been a step shy of ideal position:

“When you move him over, he’s gotta be on the line of scrimmage. That’s the whole thing,” Dykes said. “His head’s gotta break the [center’s] plane or be beyond the feet of the offensive linemen.”

Then, only the guys on the ends of the line (Nos. 1 and 7 in the diagram above) are allowed to go downfield or catch a pass. Thedford, No. 1 there, becomes the TD-scorer.

The Bama and Cal plays involved different combinations of eligible receivers, but the idea was the same. It all centers around confusion and deception.

When the play works right, the defense just covers the wrong guy. It stays with the big dude in the slot and forgets the TE on the other side.

And that’s more or less how it worked in the Bama play Dykes discovered in 2016 and the Cal play he called later that season. Most of these catches are uncontested after the defense pays attention to an offensive lineman who’ll never really be targeted, either because he’s ineligible, not athletic enough, too big, or all of the above.

But Navy’s defense played it really well and almost stopped it.

The receiver on the left side of the formation, who’s off the line, is supposed to run the cornerback away from the flat, where the ball’s going. SMU’s Myron Gailliard did that, creating an opening for Thedford.

Navy might have paid some attention to Pursley, the big slot man, or it might just have had guys sitting near him because the Midshipmen were in a zone, cover-4 defense.

But the biggest problem for SMU was that Navy’s mike linebacker, No. 54 Taylor Helflin, didn’t fall for the trick. He made a slight move toward the center of the field, then locked onto Thedford, who had just enough room to catch Hicks’ pass.

“Every time we’ve run that before, the guy’s been completely naked, wide open,” Dykes said. “And I thought Navy actually did a great job of playing it.”

It helped that Hicks threw a good ball and Thedford is 6’6.

Lashlee’s teaching point for the actual receiver on the play is simple: stay in as a blocker for just a second: “One pass set, then go.”

“Hunter did such a good job that he was able to kind of get the linebacker’s eyes pulled in for a minute,” Lashlee said. “That gave him a little bit of an advantage.”

The play isn’t rocket science. It has roots in an NCAA 14 play Lashlee used to run under his old boss and high school coach, Gus Malzahn.

The play is called “Fight Song.” It’s been a Malzahn staple since his days as a high school coach in Arkansas, and he’s used it at Auburn, including when Lashlee was his offensive coordinator from 2013-16.

It involves lining up a tight end at tackle and splitting a lineman out wide. EA Sports included it in the last version of its college football video game, and Auburn still uses it now. The Patriots used some formation and eligible-receiver trickery to fool the Ravens in the playoffs almost a half-decade ago. These tricks aren’t new.

But they still work, because athletes are human. They get confused by football’s extremely complex rules, or they hesitate.

“I can’t tell you how many times we’ll come out and a team will point out the tight end at left tackle, and then they won’t cover him,” Lashlee said. “It’s crazy.”

Navy covered the tight end, but not quite well enough.

“I think we got just enough,” Dykes said.