McDonald's has adult Happy Meals. Why grown-ups are lovin' them.

McDonald's is inviting customers to feel like kids again with the latest iteration of the Happy Meal — one that's intended for adults.

This week the fast-food chain launched the Kerwin Frost Box, a collaboration with artist and comedian Kerwin Frost (a self-proclaimed lifelong fan of the brand). Packed with a choice of Chicken McNuggets or a Big Mac plus fries and a soda, the meal is intended to spark “nostalgic joy” with its featured toy: Frost's re-creation of the McNugget Buddy collectibles, which originally launched in 1988.

Lance West, a 59-year-old based in Oklahoma, shared his excitement over the collaboration with a photo on X (formerly known as Twitter) of his own Kerwin Frost Box. “I absolutely love the nostalgia. McDonald’s was my first real job in high school, and I’ve had an affinity for the Big Mac ever since,” he tells Yahoo Life. “I’m 59 years old and feel a little awkward ordering a Happy Meal. Imagine my joy when I learned McDonald’s was offering an adult version.”

To psychology experts, this is no surprise.

“Who doesn’t want to play? Who doesn’t want to experience being a kid again without the responsibility of adulthood?” clinical psychologist Barbara Greenberg tells Yahoo Life. “There’s not really a lot of playgrounds for adults. The whole McDonald’s experience is almost like adults being once again on a playground.”

The playful, super-sized Happy Meal packaging and the included collectible make it all the more fun — even for adults who may have moved on from collecting toys.

“It's the element of surprise that adults don't get a lot of,” she says. “We need magical moments throughout the day, and as kids we have that. So I think the little toys, surprises and moments are very exciting and not what we expect on a daily basis.”

Nostalgia has a way of evoking a “longing for the past, when things may have felt easier, lighter, more carefree and overall better,” Lauren Fuchs, a senior therapist at Manhattan Wellness, tells Yahoo Life. “When a marketing campaign uses people, places, songs or things from our past that elicited joy or comfort as a child, it makes us feel young again.”

McDonald's knows that cultivating that feeling brings customers. In fact, the first iteration of the adult Happy Meal was launched with the streetwear brand Cactus Plant Flea Market in October 2022. McDonald's USA tells Yahoo Life that the campaign drove the highest weekly digital transactions in the U.S. to date. The company also plans to continue with the trend of nostalgia for the launch of CosMc's — a spin-off restaurant focused on customizable beverages,

“What would happen if a McDonald's character from the 1980s that was part alien, part surfer, part robot ... what would happen if this character were to open a restaurant in 2023?” Christopher Kempczinski, McDonald's president, CEO and director said during the company's investor day. “CosMc's is a small-format concept with all the DNA of McDonald's but its own unique personality.”

Only time will tell how successful the Kerwin Frost Box is. West, for one, plans to collect the entire set of McNugget Buddy toys.