Near the beginning of David MacGregor’s new comedy, “Consider the Oyster,” now having its world premiere at the Purple Rose Theatre, the Detroit Lions win the Super Bowl, and a young man (played Michael Brian Odgen) gets so swept up in the celebration that he impulsively proposes to his girlfriend (Stacie Hadgikosti).

Wait—what was that first part again?

“The idea is, if the Lions can win the Super Bowl, anything’s possible,” said director Guy Sanville.

Indeed, after the girlfriend says “yes,” a character's tumble over a coffee table sets off a surprising and bizarre series of events.

“It is a full-blown, fairy tale comedy,” said Sanville. “It’s got elements of farce in it, but it’s got a lot of heart, too.”

MacGregor, meanwhile, defined the play’s narrative motor in the form of a question: “If the person that you loved changed religion, or had a stroke, do you still love that person? (A significant change) makes you step back and say, ‘Well, what is it that I have actually loved about this person all this time?’ So yes, it’s a comedy. But to me, that was the question that made it worth writing.”

The play’s title, and MacGregor's point of entry for the story, stems from two intriguing, oyster-related facts that the playwright learned: first, doctors are now using ground-up oyster shells to repair human bone; and second, all oysters are born male, and then turn female.

“There are a number of animals out there … that change gender,” said MacGregor. “Sometimes they do it just once. … But there are some animals—some fish, for example—that can go back and forth, male to female, every 30 seconds, if they need to. And as you might guess, it’s a question of natural selection, and it’s a good ability to have. … For us, as human beings, we tend to view gender as very black and white. But of course, that’s not true. There are plenty of people out there who walk the line.”

Fans of MacGregor’s previous plays at the Rose—“The Late Great Henry Boyle,” “Vino Veritas,” and “Gravity”—know well that fantastical elements are one of the playwright’s hallmarks.

“It’s a way of stirring things up,” said MacGregor. “ … When things are placid and calm and structured and organized, it’s hard to see things for what they are. It’s only when things get disrupted that you can stand outside them a little bit and try to see them more clearly. And yes, sometimes what you’re trying to write about or talk about needs to be couched in fantastical terms, and this opens the audience up a bit. … This is a fantasy, therefore, they might be more receptive to what the play’s really about than they might be otherwise, if it was really pedantic and preachy.”

“I think you can create a different version of the world, and you can be fantastical and spectacular, and still, on some level, it’s a world that a person can touch,” added Sanville.

Despite the strange turn of events in MacGregor’s script, though, “Oyster” “starts off as a buddy play, about two guys who live together (Ogden and Matthew David), and it’s recognizable in that regard,” he said. “And then it just goes off the deep end a little bit. … Just imagine if one of your close friends was going through some kind of metamorphosis. That really tests—you find out who your friends are. And of course, in many respects, he’s a very irritating friend, because he’s telling the truth. And that’s the last thing he wants to hear.”

MacGregor, who studied psychology as an undergrad at Michigan State, has long been fascinated by the profound changes that can occur when people suffer an injury or illness.

“How do you know who you really are?” MacGregor asked. “You think you know who you are, but what’s going on inside you can turn you into completely different person. And it’s scary, but also kind of exhilarating, too. Life is not as cut and dried as you might imagine it is.”

Jenn McKee is the entertainment digital journalist for AnnArbor.com. Reach her at jennmckee@annarbor.com or 734-623-2546, and follow her on Twitter @jennmckee.