We won't sugarcoat it, we really miss 90s Nickelodeon. We aren't saying the new iteration of the network is bad (it sort of is...) we're just saying we miss how it used to be. Every single show that was on was amazing, and we just couldn't get enough. That said, there are still some shows in the modern era that we enjoy. The network has come a long way since its humble beginnings, with a lot of intellectual properties changing and evolving.

What hasn't changed is the fact that some shows are absolutely riddled with plot holes, continuity errors, and animation issues. Maintaining a cartoon show can be downright difficult, especially when you're dealing with a series that has spanned multiple seasons and produced a large number of episodes. Still, it's up to the creators to attempt to keep things as right as possible and sometimes they completely miss the mark.

We aren't here to bag on your favorite shows or diss any of the creative minds that brought them to life. We're simply diving into some of the more interesting errors and issues found throughout some of Nickelodeon's most popular shows. If you're like us, you're super interested when split-second animation mistakes are uncovered by a steely eye.

Join us on this journey through 15 Surprising Mistakes You Never Noticed In Nickelodeon Cartoons.

15 Chuckie's Mom

Via: Youtube (NickSplat)

Many fans of the Rugrats series remember the heart-wrenching story of Chuckie's Mom. As the episodes prattled on, we began to realize that Chuckie was the only child that wasn't represented by a two-parent household. Later in the series, we learn that Chuckie did have a mother, named Melinda. Sadly, during the "Mothers Day" episode, it's revealed that the proud parent passed away after a stint in the hospital. It's a heartbreaking story underlined by some very emotional moments and a devastating poem.

Viewers were under the impression that Chuckie's mother had passed before the "airing of the show," but one episode suggests that isn't true. In the episode "Real or Robots?," Stu tells Chuckie "your mom and dad will come pick you up in the morning," suggesting that Melinda was still alive at this point.

14 Chuckie's Other Mom

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The "Mother's Day" episode doesn't just speak about Melinda, it actually shows her. Eager fans finally got a glimpse of the one Rugrats parent that was seemingly absent from every other episode. She's depicted as around the same height as Chaz (Chuckie's father) and has orange hair (brown in Rugrats in Paris: The Movie) and freckles.

Apparently, the show's writers were unsure exactly how they wanted to handle Melinda. The second episode of season one (the first half) "Barbeque Story" features a couple scenes in which Chaz is seated next to a mysterious woman. The get-together seems to be for the families of the children so many have suggested that this woman is Chuckie's mother. In fact, she's even modeled to look similar to Chuckie and Chaz, sporting thick-framed glasses and a similar hair color.

13 The Invisible Plot Hole

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It's best to take this entry with a grain of salt. After all, SpongeBob SquarePants isn't exactly the most "realistic cartoon." To be fair, cartoons aren't supposed to be realistic, to begin with, but SpongeBob is filled to the brim with continuity errors, plotholes, and downright zany errors.

The "Pranks a Lot" episode features SpongeBob and Patrick messing around with a can of invisible spray. At one point the duo decides to "haunt" Sandy by infiltrating her Treedome and scaring her with the old "sheet ghosts" gag. As the two stand inside Sandy's Treehouse, waving their arms around, we notice they're lacking the "water helmets" required for them to walk through the fresh air of the area. We also see Sandy creating "bubbles" as she runs away, suggesting the Treedome is filled with water. To make matters even sillier, Sandy blasts through the top of the Treedome in a rocket (shattering it) but the dome is intact in the next scene.

12 Doug's Imaginary Past

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When Doug first burst on-scene in 1991, it was a welcome change of pace amid the rest of the Nickelodeon lineup. The series tackled a wide array of "real life" issues, including things like romance, friendship, bullying, and rumors. It spoke to a lot of children and teens by offering them episodes and situations which resonated with their everyday lives. Yet, it wasn't without its share of potholes.

One interesting error comes in the episode "Doug is Hamburger Boy." Doug and Skeeter are recalling a time in which the two boys were peering out the window of the Honker Burger and watching the Hamburger Boy mascot. The issue with this scenario is that the "times" in which Doug and Skeeter would see Hamburger Boy are referenced to be over a period of years. At this point in the show, Doug has JUST moved to Bluffington, making it impossible for the timeline to add up.

11 Breaking Da Rules

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The Fairly OddParents has been around since 2001, thanks to its hilarious characters, wacky storylines, and enthralling premise. Children and adults alike are constantly tuning in to catch up with Timmy as he uses his Godparents Cosmo and Wanda to grant him an array of wishes. Unfortunately, most of his wishes go array or end up fizzling out thanks to a massive book called "Da Rules."

Throughout the series, we learn about an array of important regulations, including how wishes can't be used to break true love or kill people. We also learn how using powers to win a competition is strictly forbidden. This next plothole sees Timmy do just that. In "Father Time" the youngster travels back in time to take his father's place in a race. Unfortunately, he remembers that he's not very athletic and instead uses heat vision to melt the shoes of the other racers.

10 Not Much Brain To Freeze

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Fairly OddParents has its fair share of continuity issues. Sure, it's not nearly as bad on SpongeBob, but there are moments that make eagle-eyed viewers doubletake. If you're like us, you're constantly looking for mistakes and errors in your favorite shows. It's almost like playing Where's Waldo. We aren't scrutinizing the creative process, it's simply something entertaining to do!

In the episode "Future Lost," we see a scene in which Timmy is drinking a slushie and complains about a brain freeze. Cosmo seems confused and asks Timmy what a brain freeze is before downing the slush without any side effects. However, in the episode "Go West, Young Man," there is a scene where Cosmo has been transformed into an ice cream cone. He ends up licking himself and immediately complains of a brain freeze.

9 Helga's Doppelganger

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Sometimes an error will come in the form of an animation error. There have been instances of characters changing colors or even missing limbs. Hey Arnold! suffered from a few of these animation issues but this scene is definitely our favorite. It happens during the episode "Girl Trouble," which was met with some controversy by fans due to Helga never receiving punishment for her actions.

During one scene in the episode, Helga moves from her desk to a pencil sharpener on the other side of the room. As she's sharpening her pencil, she anxiously looks back towards the class. The "camera" quickly changes to show the classroom but if you look closely you'll see that the animators accidentally included Helga in the shot. Talk about being in two places at once.

8 Harold's Wacky Teeth

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We definitely wanted to include another example of the animation errors included throughout Hey Arnold! This particular issue is front and center since it's featured on the opening of the show, rather than a specific episode. The opening is iconic, not changing much over the years (except for cleaner animation). Many people will remember the scene in which the boys and girls lineup across from one another in a "stand-off" style setting.

If you look closely at the scene in which the boys are lining up, you'll notice a curious animation error that lasts for only a split second. Harold's tooth (which can be seen constantly sticking out from the bottom of his mouth) actually swaps sides. It's easy to miss so you may need to view it a few times.

7 Confusing Buttons

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We miss Invader Zim so much. It was easily one of the best cartoon shows to ever grace Nickelodeon. Unfortunately, it only lasted two seasons, much to the chagrin of dedicated fans. It was the perfect blend of wacky humor, interesting storylines, and hilariously dark humor. Like Hey Arnold! it also featured a few moments in which the animation flip-flopped between frames.

A good example comes from the episode "Dibship Rising." During one scene, we see a "robotic screen" interacting with Dib and Gaz. The screen is used by Professor Membrane to interact with his children (since he's rarely around). Below the screen are buttons that can be used to answer "yes" or "no" to any posed questions. If you look closely, you'll see the buttons swap sides in numerous shots. It's rather easy to spot since each button is a different color (red and green).

6 No Bones About It

Via: Encyclopedia SpongeBobia

Back to SpongeBob and it's wide array of mysterious continuity issues and exceedingly strange plot errors. We love pointing these things out, but it's important to understand that SpongeBob is rather uncaring when it comes to keeping things plothole-free. The show knows that it's filled with issues and is unapologetic in its lack of continuity. A great example of this is the ever-expanding question of whether or not SpongeBob has bones.

There are many episodes in which SpongeBob is seen breaking a bone or producing a skeletal form. We've seen his skeleton on numerous occasions and the animators are rather lax when it comes to creating bones for specific gags. Yet, in some episodes, SpongeBob references that he doesn't have bones. He even refers to himself as an invertebrate and squishes his shape freely.

5 Do Ninjas Get Paid?

Via: Syfy

We grew up watching Teenage Mutant Ninja Turtles. In fact, we were so in love with the show and its characters that we gobbled up any action figures and merchandise we could. When it comes to action-packed cartoons, it's definitely one of the best animated shows to ever grace television. It didn't necessarily start on Nickelodeon but the reboot has found its home there.

Our next point is more about the lore surrounding the show than any animation errors. We see the turtles constantly devouring pizza (as evident by the massive amount of empty pizza boxes littered throughout their hideout). This begs the question, how do they afford all those pies? Are they stealing them from the shop or having them delivered? We'd love to know the answer to this question because it's bugged us for years.

4 Construction Issues

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Let's look at one more from Fairly OddParents. Continuity can be insanely difficult to keep up with in a show like this. With all of the zany episodes and elaborate wishes, it's no wonder the creators end up leaving out plot points or forgetting about the certain wishes. This issue even spreads to the environment that Timmy lives in. The Turner house has a strange habit of "changing its construction" from time to time.

Case in point, Timmy's bathroom. There have been numerous occasions in which we see a bathroom in Timmy's bedroom. The kid is living the lavish life with his own personal commode. Yet, there are many episodes in which the bathroom ceases to exist. Sometimes it's simply missing (door and all) from the architecture of Timmy's bedroom.

3 A Strange Explanation

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We know Rugrats had its fair share of plot issues, but did you know those creative errors bled into the sequel show, All Grown Up!? For those unfamiliar, the Nickelodeon series followed the Rugrats cast as pre-teens/teens. From the outside, it was pretty similar to the original series but focused on real-world issues like popularity, school, stress, and family life.

The episode "Thief Encounter," opens with a mysterious stranger stealing items from around the neighborhood. Through a series of comical events, we discover that the culprit is actually Tommy, who has been sleepwalking due to copious amounts of stress surrounding an upcoming Standardized Test. The only issue is that Tommy is seen sleepwalking before he even finds out about the test, putting the reasoning into question.

2 Disappearing Act

Via: Dreamwidth Studios

We'll be honest, this one can be considered a bit silly, but we still feel like it's a plothole. Sure, it's not nearly as glaring as all the others featured on this list but it's still pretty interesting. Those who watched Avatar: The Last Airbender were definitely aware of Aang's hidden romantic feelings for Katara. Because of this, after Katara loses her mother's beloved necklace, Aang takes it upon himself to craft her a new one.

It's a beautiful gesture and it seems like an important indicator of the duo's relationship moving forward. Yet, the neck mysteriously disappears when the group reaches the next village. In fact, no one seems to ever mention it again. Even Aang seems oblivious to the fact that Katara isn't wearing the gift.

1 Older Than He Looks

via: spongebob.wikia.com

We'll end this journey with one more look at the wacky world of SpongeBob SquarePants. This particular plot issue spans the series and The SpongeBob SquarePants Movie. We first learn of SpongeBob's age in the episode "Sleepy Time" when we see a driver's license containing his date of birth. According to the document, SpongeBob is around 14-years-old (the episode aired in 2000).

However, in The SpongeBob SquarePants Movie, we learn that the chipper sea sponge is a lot older than that. According to one scene, SpongeBob has won "Employee of the Month" 374 months consecutive times. That's a total of 31 years, which would make SpongeBob around 45 if those dates add up. What's strange is that everyone in the movie refers to SpongeBob as a "kid."