We tried the purple Grimace milkshake from McDonald's and still can't figure out what it tastes like

• McDonald's released a meal combo paying homage to its iconic Grimace character on June 12.
• Grimace's birthday meal, which includes a new flavor of milkshake, has since gone viral.

Few McDonald's celebrity meal collaborations have garnered as much attention as the fast-food giant's latest: a birthday meal for a furry, purple blob named Grimace.

Originally introduced in 1971, Grimace is one of McDonald's largely retired collection of characters that includes icons like Ronald McDonald, the Hamburglar, Officer Big Mac, and Mayor McCheese.

While some might think Grimace is a monster, he's actually meant to embody a milkshake. Weird, but we'll go with it.

McDonald's cast of characters hasn't been used in McDonald's marketing campaigns for years, but that all changed with the release of Grimace's Birthday Meal on June 12.

Grimace's Birthday Meal went viral for its inclusion of a purple milkshake and some hilarious posts featuring Grimace himself

In addition to the purple-hued shake, the meal comes with a choice of a Big Mac or 10 chicken McNuggets, plus fries. However, it was the milkshake that attracted the most attention and, as Insider reporter Chris Panella put it, invited a host of questions.

"What's in the shake that makes it purple? Probably food dye, but you can't help but wonder if it's actually made of Grimace himself," Panella wrote in an analysis of the outlandish marketing campaign, which inspired scores of hilarious memes and featured a Grimace "takeover" of the chain's social-media accounts.

McDonald's employees themselves might not even be able to describe the flavor. In one viral tweet, a user said they asked an employee what flavor the Grimace milkshake was. They got the simple reply, "Grimace."

In an effort to uncover what the Grimace milkshake actually tastes like — and determine whether it deserves the hype — we had to try it for ourselves

The medium-size Grimace milkshake cost $4.99, excluding tax, at the McDonald's location Insider reporter Erin McDowell visited. The cost of the meal at the same location was $16.08 for the Big Mac combo and $15.68 for the meal with the 10-piece nuggets.

Some McDonald's customers have complained about the varying price of the meals depending on which location they visit. One Twitter user claimed their local McDonald's was charging upwards of $20 for the Grimace-themed meals. The price of the meal, like all other McDonald's menu items, is determined by "each individual restaurant and may vary based on location," McDonald's said in a statement to NBC.

Back to the milkshake: The violet-colored drink comes in a birthday-themed cup covered in illustrations of colorful confetti, with a delicate swirl of whipped cream on top.

Insider reporter Chris Panella bought the Grimace shake three times over the course of a few days and noticed that each shake was a different shade of purple. One was much brighter and vibrant. The next was a bit less purple and more blue. And the last had an almost off-white color.

By just looking at the milkshake, you'd have a hard time guessing what the flavor is. Grape? Blackberry? There was only one way to find out.

We thought the milkshake tasted like a cross between a generic berry flavor, vanilla, and birthday cake

The sweetness of the milkshake wasn't overpowering, but it was definitely there. The texture was smooth, and could easily be slurped through a straw.

It was hard to distinguish exactly which berry it tasted like — after a couple of sips, a distinct blueberry flavor started to come through. However, it felt far from eating fresh blueberries in the summer.

McDowell thought the shake had a slightly artificial flavor, only heightened by what tasted like vanilla extract flowing through it. It also tasted slightly like birthday cake — but that could have been a placebo effect of looking at the birthday-themed cup.

"It's good, but I'm not sure if I would go out of my way to order it again," McDowell said after trying it for the first time. "Maybe I'm just more of a chocolate milkshake kind of girl."

Panella's first shake tasted like blueberries, but his second and third shakes just tasted ... purple. "It was like Fanta grape soda, really artificial and fake," he said. "I'm kind of obsessed with how it tastes."

After all the online chatter surrounding Grimace's milkshake, we were left a little underwhelmed

For a giant, furry blob created to embody the essence of a literal milkshake, we thought the flavor was pretty tame.

While it was nothing to grimace over, it just didn't pack the punch we were expecting. But Panella said he'd get it again just for the meme, even though it wasn't as flavorful as a Shamrock Shake or as immediately classic as a chocolate, vanilla, or strawberry McDonald's milkshake.