Most Nickelodeon cartoons were designed to be wholesome and kid-friendly. As kids, we never really expected these shows to feature anything that would be considered as grown-up. However, most of these programs actually had loads of references that weren't even meant for kids! Most of us never really understood them simply because we were just too young. The thing is, a lot of these references are cleverly hidden.

Some references go by so fast that most kids won't even notice them. What might seem like a prosaic conversation might actually be a sneaky reference that only grown-ups would get. Cordial exchanges between two seemingly innocent cartoon characters might even contain a clever joke or two! These references aren't just limited to witty quips and comedic gestures either. There are some that are basically hiding in plain sight. From billboard signs to snazzy lines, there's always an unassuming reference hiding in the seams of these supposedly child-based Nickelodeon shows more often than not.

These instances didn't make much sense when we were kids, but as grown-ups, we can now understand the true meaning behind the clever writing in some of our favorite Nickelodeon shows. We can finally appreciate the hilarious references that likely snuck past our eardrums back then. But don't scream “childhood ruined” just yet! Most of these references are actually quite educational instead of being just plain off-collar. So let's take a trip down memory lane and revisit 25 Nickelodeon cartoon references that would've made our parents chortle or perhaps even raise an eyebrow.

24 Mankind's Bad Habits (Aaahh!!! Real Monsters)

Via: The Cricket Gallery

During the pilot episode of Aaahh!! Real Monsters, there was a scene where Ickis was gossiping about how humans were throwing away eggs. Oblina then gasps in disgusts exclaiming “Why would anyone want to throw perfectly rotten eggs?” Ickis responds saying “Humans, go figure.”

Even monsters are perfectly aware of mankind's folly.

Kids might not get the reference since they're probably unaware of how wasteful they are. Humans are generally wasteful creatures so Ickis knows what's up. After all, he does live in a huge garbage dump that was created by humans in the first place.

23 Jazz In The Beaver Dam (The Angry Beavers)

Via: MTV

The “Endangered Species” episode of The Angry Beavers contains a cleverly hidden reference that no kid would get, unless they know their classical jazz, that is. In this episode, Scientist Number One and Pete are watching the beavers. After their cover was blown, the scientist spews out a slew of idiomatic expressions.

One of these was the line “The catfish are jumping and the cotton is high.” The last line is actually part of the iconic 30s jazz song “Summertime.” Even adults might not get the reference if they're not musically-inclined, so the chances of kids noticing it are quite slim.

22 Stu's Parenting Woes (Rugrats)

Via: Youtube (dezc0ri)

Everyone who's familiar with the Rugrats episode “Angelica Breaks a Leg” would certainly recall Stu's iconic line. After all, the words “I've lost control of my life” was forever immortalized as a popular meme. That doesn't mean every kid back then actually understood what it really meant though.

Adults struggling with parenting issues will cry both tears of laughter and sorrow upon hearing Stu's depressing sentiments. We can only imagine how hard it is to please a spoiled niece like Angelica. Reality really can get so ridiculously bad at times that we just can't help but laugh.

21 Grandma Pookie's Trash Talking (Hey Arnold!)

via Youtube.com

Hey Arnold is no stranger when it comes to inserting words with double-meanings into their dialogue. A perfect example can be found in the episode “The Old Building.” In one segment, Ernie was having an epic verbal squabble with Arnold's grandma.

Grandma Pookie ends up calling Ernie a “homewrecker.” Kids might've taken this literally since Ernie does wreck homes for a living. However, adults would be snickering since it also means a person who's responsible for breaking up a marriage! Whether it's taken literally or figuratively, this joke will certainly have both kids and adults laughing.

20 SpongeBob's Secret Hair (SpongeBob SquarePants)

via Dailymotion.com

Fans know that SpongeBob SquarePants is an odd fellow but in the episode “The Smoking Peanut,” he's acting more peculiar than usual. There's a scene here where SpongeBob tells Sandy “I'll go get my hair cut.” Sandy suddenly comes up with a startling realization exclaiming “SpongeBob doesn't have hair, or does he!?”

Who knows what anthropomorphic sponges grow during puberty.

Some kids might not even notice this seemingly innocent reference but it will surely have adults raising their eyebrows. The way Sandy delivers the line makes us also wonder, does SpongeBob really have hair anywhere?

19 Steelie Phil's Street Lingo (Hey Arnold!)

via Dailymotion.com

The Hey Arnold episode “Back To School” showcases grandpa “Steelie” Phil's hard-nosed reputation. In this episode, Phil managed to attract the attention of the police due to his mischievous behavior. Once the police finally arrive, Grandpa Phil shouts “Run! It's the man!”

Adults would certainly feel Grandpa Phil's pain.

Now, kids might be wondering, why would Phil refer to a group of cops as a single man? Well, that's because Phil was using a slang term that refers to any body of authority. Once we're old enough to deal with government figures ourselves, we'll probably be saying the same thing.

18 Peter's Ear-Aching Hobby (Rocko's Modern Life)

via Youtube.com

Peter Wolfe might not get much airtime on Rocko's Modern Life but when he does, he's usually spotted wearing his signature shirt. Band shirts are quite popular during this era and Peter's naturally following the trend. The thing is, Peter's shirt blatantly says “Ear Deth.”

This is a jab to the heavy metal music genre. Many consider the ear-splitting sound of heavy metal music as the cause of an ear's demise. While this might have had many adults cracking up, it would've also taught kids some questionable spelling. Yikes!

17 The Choking Lizard (Rocko's Modern Life)

via Youtube.com

Fans of Rocko's Modern Life know that there's a food chain called Chokey Chicken but did they know that there was a choking lizard as well? During the episode “Teed Off,” a Conglom-O lizard instructs the groundskeeper on how to help his boss win the golf game. The lizard then begins to start choking intensely, out of nowhere!

The groundskeeper then becomes befuddled, unaware that his resemblance to an iconic villain is causing the predicament. Any Star Wars fan knows Darth Vader's force-choking tendencies but kids who aren't might feel just as confused.

16 From Icons To Insects (The Ren & Stimpy Show)

via Dailymotion

The Ren and Stimpy Show paid homage to iconic 50s entertainers by turning them into, well, insects. However, adults might have a hard time recognizing some while kids might not recognize them at all! In the episode “Sammy and Me,” Stimpy gets starstruck after sighting celebrities such as “Peter Locust,” “Dean Mayfly” and “Liberoachy.”

These characters are apparently based on 50s icons like Peter Lawford, Dean Martin and of course, Liberace. Unless kids back then grew up enjoying 50s entertainment, these references will most likely be ignored like a fly on a wall.

15 Real-Life Comedy Meets Comics (KaBlam!)

via Youtube.com

KaBlam! Is known for breaking the fourth wall when it comes to their skits and in the show's 36th episode, they did just that. In one segment, Henry is seen smashing a honeydew melon using a comically large mallet. His co-host June then corrects him saying that he should be using watermelons instead.

If you didn't get the joke's appeal as a kid, then you're not alone. June was actually referring to the real-life comedian, Gallagher, who's famous for smashing watermelons! It's kinda hard to recognize stand-up comedians especially when we could only watch cartoons at the time, right?

14 The Hospital That Stings (Sniz & Fondue)

via Youtube.com

While most shows present comedy through hilarious skits and witty lines, Sniz & Fondue hides comedy gold in plain sight. A perfect example would be in the episode “Stuntbike Sniz.” When Sniz had a motorcycle accident, he was sent to a hospital called “Rudolph Shanker.”

Some jokes aren't even told at all, they just sit there, waiting to be noticed.

If adults find that name familiar, that's because it sounds strikingly similar to Rudolf Schenker, founder of the rock band Scorpion! It's safe to say that Sniz would definitely be feeling that sting in the next couple of days.

13 Foul-Mouthed Figurines (Action League Now!)

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The Action League Now! episode, “Where Pigeons Dare,” shows that even adults could find action figures entertaining. In one scene, some mischievous little toys are shown throwing eggs at passing cars while yelling “Eat yolk, yuppie scum!” Kids who didn't get the reference are probably too young to know about it.

This term was practically used as a derogatory remark back in the 80s, towards obnoxious and arrogant young professionals. This just goes to show that even toys can recognize a yuppie when they see one.

12 Heffer The Movie Buff (Rocko's Modern Life)

via Youtube.com

Rocko's Modern Life's Heffer just proved that he's a certified film buff during the episode “Road Rash.” Heffer was talking Rocko into going on a road trip. He then mentions “Peter Fondu” and the “Greasy Riders” as “one of the greatest road-trippers of all time.”

It wouldn't be easy for kids to recognize any of these riders.

Adult viewers would certainly be familiar with these names as they're a parody of the 1969 cult classic Easy Rider starring Peter Fonda. Now that we're all grown-up, we can finally get the reference but ol' Heffer was already way ahead of us.

11 MeltMan's Fashion Statement (Action League Now!)

via Youtube.com

In the conclusion of the Action League Now episode “Where Pigeons Dare,” MeltMan is seen being swallowed whole by a snake. He then says “Don't worry, I look good in snakeskin.” MeltMan's punchline sends the entire Action League team laughing, except for some of the younger viewers, that is.

Anyone who's at least trendy knows that MeltMan is taking snakeskin fashion way too literally. Of course, the writers don't exactly expect kids to have snakeskin suits in their wardrobes so the joke wasn't entirely intended for the little ones.

10 Loopy Solves A Famous Mystery (Life With Loopy)

via Youtube.com

The Life With Loopy episode “20,000 Leagues Under The Sofa” features a real-life mystery that no kid would've gotten back then. In this episode, Loopy finds herself in an underground world deep within their sofa, in hopes of finding her brother's beloved baseball. This place houses most lost items, which apparently includes lost people too!

Too bad Loopy wasn't looking for lost people.

While loopy was descending via an elevator, the PA system announced “level 94, Jimmy Hoffa.” Hoffa was an influential labor union leader who disappeared back in 1982. Looks like he was just hiding underneath the couch all along!

9 Daggett's Hygiene Problem (The Angry Beavers)

via Youtube.com

There are lots of things in The Angry Beavers that kids might not get given its witty dialogue, quips, and fast-paced banter. Norbert's constantly-changing accent and inflections alone are enough to confuse some kids. That said, there's a joke in the “Practical Jerks” episode that might have went passed the heads of many kids back then.

This is when Norbert found his underwear that's labeled “Wednesday.” Daggett then says “that's funny, mine say October.” Kids will be scratching their heads until they finally realize that Daggett goes through a full month using the same underwear! Oh, the horror!

8 The Legen(Dary) Teenage Doctor (Rugrats)

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The episode “Angelica Breaks a Leg” also contains an unexpected cameo that only adults would get. This episode featured a genius teen doctor known as Hoagie Dooser. Sound familiar? Probably because he reminds us too much of the popular Doogie Howser M.D. Series.

Hoagie Dooser's Dr. Howser impression is quite legen, wait for it, dary!

As if his name isn't already too much of a giveaway, Dr. Dooser even plays the teenage doctor convincingly! The part when Hoagie reminds Stu of his credibility as a doctor despite his childish nature, is enough to make adults rolling.

7 Debbie's Aussie Slang Encounter (The Wild Thornberrys)

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Debbie Thornberry showed in the episode “Born To be Wild” that she shouldn't be taken lightly. The episode sees Debbie hoping to borrow a surfboard. However, the surfers underestimated Debbie's capabilities telling her “that stuff's pretty demanding Sheila, it ain't easy.”

After being constantly berated by the local surfers, Debbie finally snaps telling them “don't ever call me Sheila!” Kids obviously know that Sheila isn't even close to Debbie's name. What they might not know is that Sheila is actually an Aussie slang for girl. Too bad in this case, it's being used in an insulting manner.

6 Ginger's Awkward French Date (As Told by Ginger)

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As Told by Ginger is filled with awkward moments that most kids haven't even experienced yet. The title alone of the episode “Stealing First” might be enough to leave children puzzled. In this episode, Ginger is on the verge of kissing French exchange student Jean-Pierre.

However, Ginger hesitates and ruins the moment. She then tells her friend Darren “I didn't know how to French Kiss.” Just because Jean was French doesn't mean he was going to give her a French kiss. In fact, the French didn't even come up with the term! Well, at least the kids are with her on this one.

5 Dog's Menacing Statement (CatDog)

Dog is usually a friendly character in most CatDog episodes, just not in “Fistful of Mail!” This is the episode where he delivers the famous line “let's get postal!” Younger viewers might not get the reference since it's quite a grim term.

It's usually associated with crazily angry people, mostly postal workers, who go on a violent rampage. In Dog's case though, it's quite appropriate since he's going to face an actual post-boy, and dogs love chasing mailmen! Besides, there's no better way to prevent them from going postal than taking the fight straight to them, right?