YOU NEVER KNOW what to expect when you walk into a Marc Jacobs fashion show in Manhattan. This is a designer who’s sprung everything from collegiate marching bands to latex-covered rubber rooms on attendees. And his spring runway set didn’t disappoint: a nearly featureless Brobdingnagian pink house that appeared to have been magically dropped by a Kansan cyclone onto the matching gravel.

“A lot of people said Barbie Dreamhouse,” set designer Stefan Beckman commented. “But that was never our intention.” Mr. Jacobs, however, didn’t entirely explain the point of the rosy dwelling, leaving it open to interpretation. And the shade of pink he deployed, optimistic almost to the point of sickening, is, in fact, a bit of a Rorschach test. It could soothe as much as unsettle. And it could reveal how conformist you are. In today’s fashion and design worlds, pink typically falls outside the monochrome cool school. It’s outré—and therefore useful if you want to shock, and possibly delight.

No wonder then that stylist Mel Ottenberg chose a bubble-gum-hued dress—an haute couture confection by Giambattista Valli—for his client Rihanna to wear to this year’s Grammys. “I wanted to have fun. I didn’t want anything safe,” said Mr. Ottenberg. “I didn’t even necessarily want something that everyone would like.”

Mr. Ottenberg and the pop singer have been on something of a pink streak. In just the past two weeks, he’s put her in a powder-pink latex coat by British designer Holly Fulton for a screening of Rihanna’s new film, “Home,” in a pink-and-black gingham Adam Selman dress for a Snapchat Q&A, and, for an appearance on “Good Morning America,” in a candy-colored matching jumpsuit, jacket and fur stole by French designer Pascal Millet.

“Pink is really strong right now,” he said. “I feel like it’s all over the place.” It’s showing up in unexpected executions, like the latest collection by Parisian label Pallas, which has built its name on tuxedo-inspired tailoring. This spring, designers Daniel Pallas and Véronique Bousquet spiked their array of black, white and navy-blue looks with searing fuchsia ones. Though those pieces have been picked up by many retailers, they may not be an easy sell. “You must be strong to wear a tuxedo, and even stronger to wear it in pink,” said Mr. Pallas.