“Splish splash, I was taking a bath, long about a Saturday night” … Why get all splishy-splashy by your lonesome when you can rub-a-dub-dub with 90 oddly costumed, exceptionally limber elves springing out of a fever dream—plus 1,800 strangers around you in a place that looks less like a bathroom than a 14th-century opera house? That’s one hell of a tub they’ve got at “O,” the Cirque du Soleil aqua-ganza now in its 19th year at Bellagio. You can bathe in its production pleasures not just on Saturdays, but Wednesdays through Sundays at Bellagio. Oh, yes: “O” is pronounced the same as the French “eau,” meaning water—the show’s concept celebrating its “infinity.”

“Just singin’ in the rain, what a glorious feeling, I’m happy again” … How about clownin’ in the rain? Say, two preshow jesters who tickle the crowd with silly shtick, employing a giant rubber raft, an umbrella (fending off rain effects from the domed ceiling) and water bottle spritz fights (and later do pratfalls on a floating houseboat, babbling Cirque’s signature nonsensical language. You know it as gibberish).

“Like a bridge over troubled water” … Just wondering: What does troubled water look like? Does it have waves with worry lines? Anyway, the water is actually a pleasing blue-green in a specially designed pool that holds a whopping 1.5-million gallons of water (and gets regularly drained into the Bellagio Lake), delves down 25 feet, is maintained at 88 degrees and, beneath the surface, hides 15 safety experts who guide the artists to their breathing regulators.

“Sittin’ on the dock of the bay, watching the tide roll away” … Yes, it’s like watching a tide come and go, thanks to the pool’s ability to both contract (occasionally conceding to an actual stage) and expand.

“Another glimpse of a madman across the water” … Well, “mad” is one way of putting it. “Courageous,” “talented” and “daring” are other descriptions of the gymnasts, acrobats, trapeze artists, synchronized swimmers (who will remind Turner Classic Movies buffs of Esther Williams’ aquatic spectacles) and divers (who take graceful—nay, elegant—plunges from a dizzying—nay, batty-110 feet up).

“Moon River, wider than a mile, I’m crossing you in style someday” … “Style” is underselling it. Characters in this faux river include a wicked transvestite (seriously), comets, a masked thief, an abandoned bride, a rubber man, a chicken and Napoleon. Several breeze by on a crocodile float and carousel water horses, and a pianist (and his piano) descends into the pool. Don’t ask what it all means-it’s a typical Cirque-a-delic Rorschach test.

“Smoke on the water, a fire in the sky” … Yes, there’s a fire juggler—a pyromaniac who sets himself aflame. Perhaps he’s how they keep the pool temp at 88 degrees.

“Up a lazy river by the old mill stream” … Lazy? LAZY? Hardly. Laziness is a luxury

when you perform on aerial hoops and parallel bars on a boat-shaped platform above the water, swing through an artificial rainstorm and execute contortions.

“Splish splash, I jumped back in the bath, well, how was I to know there was a party goin’ on?” … Look onstage. How could you NOT? Now put on a towel, will ya?

Bellagio, 7 & 9:30 p.m. Wed.-Sun. (dark Feb. 5), $98.50-$155 plus tax and fee. 702.693.8866