Midway through a weeknight tasting-menu dinner at the French Laundry, a server wheeled a slim side table up to mine and walked away, leaving me and my dining companion perplexed. Were they going to cut something up table side, like Peking duck? Would the sommelier come by to play three-card Monte with us? I thought I knew what to expect when I walked in: This moment of apprehension was almost refreshing. Fool that I was, even then I didn’t think the kitchen could surprise me all that much.

That’s when they brought out a glass bong, a foot-long round-base number with rivulets along its tube and a sea of blue and green swirls at its base. The kind you use to smoke drugs. Plumes of white smoke poured out of it as it stood high, with the kind of boldness that I’m terrible at faking when I walk into rooms like this one. That shouldn’t be here, I thought, feeling the curious gazes of the fancy folk who’d paid good money and donned blazers — as per the dress code — to earn their places in the dining room that night. They didn’t get a bong.

“When Pete Wells reviewed Per Se, he compared the mushroom bouillon to dirty bong water,” the server said as he pulled the bowl and stem out of the instrument with the same flourish he’d surely use to uncork a bottle of wine. “So this is a play on that review.”

He winked at us as he poured porcini mushroom broth — indeed, the color of rancid bong water — into my bowl. I marveled as it cascaded over the vegetarian “pot-au-feu” of carrots, oxheart cabbage and a layer of leeks wrapped around black winter truffle confit, made to look like a beef bone. It was a brilliantly executed in-joke.

After dinner, I emailed the French Laundry’s public relations people about the bong. In an email, they responded that it’s something Thomas Keller pulls out for restaurant industry folks because he knows we’d get a kick out of it. (This is true. And Keller knows me from a previous encounter during my past life as a New Orleanian line cook.)

“It is clearly a tongue-in-cheek reference to past writing and is not on the menu,” they wrote, “but regularly prepared for guests as a fun item.” When I pressed them on where the bong was actually from — obviously not Riedel or Zalto — all they would say was that it was “hand blown by an artisan.” (I’m just going to stick with my fantasy image of Keller sending one of his externs to Napa Smoke N Vape with $50 in cash the day after Wells’ review dropped.)

In-jokes aside, there’s an argument to be made that the bong fits in perfectly at the Laundry, a restaurant that played a key role in the American modernist food scene. Consider modern art where the surprising context of an object is the point. Think about Claes Oldenburg or Jeff Koons, who use objects with vernacular resonance — like giant office supplies or a balloon dog crafted from polished steel — to transplant awe into things we usually don’t think twice about. By bringing banal objects into art spaces like the gallery or museum, the artists make these familiar things alien, and we viewers are prompted to step outside of ourselves and reconsider the shapes and colors that we’ve grown used to glazing over every day.

The same happens when a colorful glass bong, one that could have been stolen from any college kid’s dorm room, is brought into the French Laundry. Like the little mermaid combing her hair with a fork in a ballroom, the bong’s anarchic presence creates an art moment, a happening, in an otherwise staid dining room. Though the official stance is that it’s an in-joke, an expression of “Oh, those wacky critics!” to be shared among restaurant industry colleagues, I think it’s more than that.

It’s fascinating to think about how Keller, a famously careful and perfectionist chef, that classic swan gliding effortlessly through the water while its feet churn underneath, metabolized the stress from Wells’ review of Keller’s Per Se in Manhattan. It would be easier to just let go of the past: to put bad memories aside and assure yourself that history won’t repeat itself.

But for him to parade those memories in front of people — in front of a critic! — is a much braver tack. It comes off as a subtle tugging at his collar: a moment of chaotic energy to show that he’s learned from his mistakes.

As for what I thought about the rest of the meal? More on that later.

Soleil Ho is The San Francisco Chronicle’s restaurant critic. Email: soleil.ho@sfchronicle.com Twitter: @Hooleil