It began as a strange and unnatural occurrence, like one of those unverified online photos of a chimp hanging out with a bird. Now it's threatening to become a bizarre tradition, or, as the kids so eloquently put it, ''a thing.''

Every four years or so, the Vikings should steal one of the Packers' best offensive players, just to create the kind of sideshow that can make even training camp interesting.

In 2009, and 2010, and into 2011, Brett Favre turned the already fascinating Vikings-Packers rivalry into something it had never before been on any meaningful level: incestuous.

In 2013, Greg Jennings is one-upping Favre, not in terms of existential angst and passive aggressiveness, but with new-age, self-aware, YouTube-able, Twitter-ready, Facebook-enflaming, border-crossing Scud missiles designed to invoke an emotional response even if they miss the target.

Jennings, the new Viking and former Packer receiver, is, as the kids say, ''trolling'' his former team. If you're too young to know what ''trolling" is, just listen to Jennings a few times, and you'll get the idea.

In July, in an interview with the Star Tribune's Dan Wiederer, he poked holes in the flawless image of Packers quarterback Aaron Rodgers, raising or confirming questions about Rodgers' ego and leadership skills.

This week, Jennings told KFAN that the Packers had ''brainwashed'' him into believing that Green Bay was the land of milk and honey-flavored cheddar, that operations such as the Vikings were inherently flawed.

If true, that's fascinating. If not, Jennings is fascinating.

Just as Favre sought the Vikings because he wanted to beat the Packers twice a season, Jennings is demanding to become the focus of the best rivalry in the Upper Midwest.

I don't know if that's good or bad, whether it will elicit the best from Jennings or turn him into a punchline, but the man is intent on being an entertainer, during August, when only a good baseball team or a fantasy football draft can save the average sports fan from summer torpor, and for that we should be grateful.

Like a man running into a burning building, he's either brave or foolish, depending on whether the roof crashes on his head.

Ryan Longwell moved from Green Bay to Minnesota without raising much fuss. He was too classy and professional to inflame the rivalry. Plus, he's a kicker, more like a golfer than a football player.

Darren Sharper moved from Green Bay to Minnesota, but while he was verbose, he was also cautious. You could read between the lines, but he wouldn't read them for you.

Those were the most accomplished players to move one state west from Wisconsin in recent history and with tread left on their tires. And if they fired any shots at their previous employers, they did so with Nerf guns.

Favre and Jennings have taken a great rivalry and made it even more personal, made it, as the kids say, ''pop.'' It's as if Burr and Hamilton made ''Yo' Momma'' jokes before they drew.

There are differences between the Vikings and Packers fan bases that rise above stereotypes. Packers fans are buoyed and bolstered by their Super Bowl titles, by the legend of Vince Lombardi, by the central role the Packers play in the lives of all who live in the littlest town in the NFL. Packers fans are optimistic even when there is no reason for optimism.

Vikings fans are paranoid, burned by too many big-game losses, proud of individuals but shamed by teams, and aware that being a Vikings fan is more a choice than a legacy. Vikings fans are pessimistic even when there is no obvious reason for pessimism.

Vikings fans shouldn't have celebrated Favre's motives. He was using Minnesota to exact revenge.

Jennings is different. He's a talented player in his prime who chose Minnesota for competitive, as well as financial, reasons.

And now that he's wearing purple, he's practicing acupuncture, skillfully needling the soft tissue of a great and self-referential franchise.

As the kids say, ''More, please.''

Jim Souhan can be heard weekdays at noon and Sundays from 10 to noon on 1500 ESPN. His Twitter name is @SouhanStrib. • jsouhan@startribune.com