Patrick Star may not be SpongeBob SquarePants’ best friend after all.

That title may actually belong to Tom Kenny, the voice behind the cartoon sponge who has spent the past 25 years learning everything inside the brain of the famed Krusty Krab fry cook—well, everything except the elusive Krabby Patty secret formula.

“SpongeBob knows it,” Tom exclusively told E! News Oct. 7 at The Krabby Patty Kollab, an event that brought SpongeBob SquarePants’ iconic Krabby Patty into the real world in celebration of the series’ 25th anniversary. “He wouldn't tell Tom Kenny about it. We're close, but even he and I aren't that close. He would never tell me. We're as close as two people can possibly be. But he still would not divulge the Krabby Patty formula to me.”

Even if Tom doesn’t know what goes into the Krabby Patty—which can now be found on menus across the US, as restaurants like Wendy’s put their own spin on it—he has a hunch about what the burger does not contain.

“I'm pretty sure it's not fish-based, because that would be cannibalism,” Tom joked. “That's as far as I can go. My knowledge of Bikini Bottom food culture is limited.”

However, his costar Carolyn Lawrence—the voice behind SpongeBob and Patrick’s friend Sandy Cheeks—feels more confident about the primary ingredient in the top secret Krabby Patty.

“I know it sounds so dorky: I really think it's love,” Carolyn told E!. “Dorky, but true. I think it's the love that SpongeBob puts into cooking.”

As for Mr. Lawrence, who portrays The Krusty Krab’s nemesis Plankton, he quipped that he’s “going to completely analyze” the recipe after tasting the real-life version, because he still doesn’t know what’s inside the cartoon comfort food. 

But other than his confidential cooking techniques, Tom noted that SpongeBob doesn’t keep many secrets from his fellow Bikini Bottom residents, who the voice actor sees as “somewhere between 4 and 8 years old” to help him get into character (though Nickelodeon’s official stance is that they are ageless).

“SpongeBob is such an open book,” Tom continued. “I don't really know that he has any secrets or anything unplumbed because just as a character, his whole thing is being open. Much to Squidward’s chagrin. SpongeBob lets his freak flag fly and he still does. He's very unself-conscious, which I like. So, I don't think SpongeBob has any cards that he's been holding close to his vest for a quarter century. I think it's all out there.”

While waiting to learn what is actually in the secret formula, read on to learn more surprising facts about your favorite animated characters.

Many fans were left purrrrrfectly confused after this revelation.

“Hello Kitty is not a cat,” Jill Cook—an executive at Sanrio, the company behind the character—explained to Today July 18. “She’s actually a little girl born and raised in the suburbs of London. She has a mom and dad and a twin sister Mimmy who’s also her best friend. She enjoys baking cookies and making new friends.” 

While the news may have surprised some, Cook wasn’t the first to share this insight. As a matter of fact, Christine R. Yano—a professor of anthropology who penned the book Pink Globalization: Hello Kitty's Trek Across the Pacific—had also previously confirmed that Hello Kitty isn’t a feline.

“Hello Kitty is not a cat,” she told the Los Angeles Times in 2014. “She’s a cartoon character. She is a little girl. She is a friend. But she is not a cat. She’s never depicted on all fours. She walks and sits like a two-legged creature. She does have a pet cat of her own, however, and it’s called Charmmy Kitty.”

Other fun facts about Hello Kitty? According to Sanrio, she is five apples tall, weighs three apples, was born on November 1 (making her a Scorpio) and dreams of being a pianist or poet. 

Gawrsh! Did you know this fact? 

Bill Farmer, who's provided the voice of Goofy for decades, explained why the Disney character can talk while Mickey Mouse's pet Pluto can't.

Goofy is "not a dog, but he's a canine," the voice actor said on an August 2024 episode of Popcorn Podcast with Leigh Livingstone and Tim Iffland. "So it's kind of like a wolf is not a dog but it's a canine—same thing. Goofus canis, that's what he is. Or, he's a MOG—he's a man-dog."

However, Pluto, he added, is a "regular dog"—a blood hound as it turns out.

You'll want to get to the (bikini) bottom of this discovery.

SpongeBob SquarePants' creator Stephen Hillenburg once revealed that Squidward Tentacles is actually an octopus—not a squid.

"This is Squidward the Octopus, SpongeBob's grumpy next-door neighboor," he shared in the 2005 Case Of The Sponge 'Bob' video resurfaced by BuzzFeed. "I like the octopus for this character because they have such a large, bulbous head, and Squidward thinks he's an intellectual so, of course, he's going to have a large, bulbous head."

But if you're wondering how Squidward can be an octopus when he has only six legs instead of eight, Hillenburg had an answer for that, too—noting "it was really just easier for animation to draw him" with fewer tentacles.

Break out your handy dandy notebook and jot this one down.

"One of the things that nobody knows is that Blue was originally a cat," the show's co-creator Angela Santomero said in the 2006 special Behind the Clues: 10 Years With Blue resurfaced by Mental Floss. "First his name was Mr. Orange and then we're like, 'Uh, maybe Mr. Blue.'"

But according to the special, Nickelodeon was already working on a series about a cat—leading animators to toss out the original idea and redesign Blue as a dog.

Now this really isn’t funnie, er, funny.

But as it turns out, Doug Funnie from the cartoon series Doug was almost named Brian. As for what led to the change?

"I just thought Brian was too fancy of a name," Doug creator Jim Jinkins told HuffPost TV in 2014, "So, I geared it down, and started calling him Doug. If you think about what that sounds like, it sounds incredibly average, and that’s what I was trying to do: express from that point of view.”

This fact is so good it’s scary. 

In Monsters, Inc.: An Augmented Reality Book, the name of Boo—the little girl who accidentally ends up in Monstropolis and befriends monsters Mike and Sulley—is revealed to be Mary Gibbs, according to BuzzFeed. And if the name sounds familiar, it’s because it’s the real-life moniker of the actress who provided the voice of Boo. 

Need more proof? In the movie, there’s actually a scene where Boo is sorting through some of her drawings and fans can spot the name “Mary” scribbled at the top of one of the pieces of paper.

Speaking of names, while Mickey Mouse’s girlfriend is often called Minnie Mouse, according to the BBC, it was revealed in 1942 that her full name is actually Minerva.