Nickelodeon Animation Studio

Background
Nickelodeon Animation Studio (also known as "Nicktoons Productions"), the animation unit of Nickelodeon, was established from Games Animation in 1990, and is best known for producing Nicktoons such as SpongeBob SquarePants, Hey Arnold!, The Fairly OddParents, Danny Phantom, The Loud House, and others. The unit also produces Nick Jr. programs such as Blaze and the Monster Machines, Shimmer and Shine, Wallykazam!, and Butterbean's Cafe.

Logo (April 19, 1997-July 19, 2009)
Visuals: On a black background is the Nickelodeon splat logo with "NICKTOONS" replacing "NICKELODEON" on a black background (although sometimes it reads "NICKELODEON" and is stretched out more). Copyright information is seen below, or sometimes not at all.

Trivia: If this logo has been shown after Nickelodeon USA's split-screen credits, sometimes the name of the show in the copyright notice is shortened down, usually awkwardly (e.g., My Life as a Teenage Robot becomes Teen Age Robot, and Oh Yeah! Cartoons becomes Oh Yeah!).

Variants:
 * On some shows such as Invader Zim, ChalkZone, The Adventures of Jimmy Neutron: Boy Genius, and El Tigre: The Adventures of Manny Rivera, the copyright info is written in the same font as the credits.
 * On Avatar: The Last Airbender, the logo is superimposed over the closing credits.
 * On some split-screen credits airings of Invader Zim, the copyright doesn't appear for a few seconds.
 * On Oh Yeah! Cartoons, the words "Produced at the Nickelodeon Animation Studios, Burbank, California" are between the logo and copyright info.
 * On Garlic Boy, the logo is smaller and tilted to the right.
 * On some international prints of Nickelodeon shows on non-Nickelodeon channels (such as on foreign Disney Channel airings of The Fairly OddParents), the Nicktoons logo is completely removed, leaving just the copyright.
 * On Charlotte's Web 2: Wilbur's Great Adventure, the logo lacks copyright info.

Technique: A still image.

Audio: The closing theme of the show, a soundbite of the show, or silent.

Audio Variants:
 * On The Adventures of Jimmy Neutron: Boy Genius, there is the theme song's opening riff and Jimmy (voiced by Debi Derryberry) saying "Gotta blast!".
 * Usually for the split-screen credits, it's the same as the original credits (including Jimmy saying "Gotta blast!"). In the case of Invader Zim, however, two variants were used. One was the synth drone and electricity sparking from the start of the episode "The Nightmare Begins" (which was the most common), and the other was a modified version of Zim (voiced by Richard Steven Horvitz) laughing at the end of the opening theme.
 * On 2005 airings of Avatar: The Last Airbender, a glitch happened where the superimposed version showed after the split screen credits with the kids laughing audio.

Availability:
 * The "Nicktoons" variant is preserved on digital releases of most non-Klasky Csupo Nicktoon from The Angry Beavers to Danny Phantom. It was also seen on The X's, which has never seen a rerelease, and hasn't been reran since 2015. However, DVDs and VHS releases of SpongeBob SquarePants and The Fairly OddParents often use the Nickelodeon Productions haypile instead.
 * The 2009 Nickelodeon Productions logo usually plasters this on reruns. Even NickRewind on TeenNick is replacing this logo with said logo during split-screen credits (Angry Beavers is one show that still retains this logo because there is no split screen credits at the end).
 * Hey Arnold has this logo plastered by the one of the 2017 Nickelodeon Productions logos on NickRewind, but VOD prints retain it (season 1 episodes have the haypile logo); it's the same purpose for both CatDog and The Angry Beavers.
 * The "Nickelodeon" variant first appeared on The Adventures of Jimmy Neutron, Boy Genius, and was used concurrently with the "Nicktoons" variant until around 2006, when it effectively replaced that version. It also appeared on My Life as a Teenage Robot, Avatar: The Last Airbender, Catscratch, non-US/Canada airings/prints of early El Tigre episodes, non-US/Canada prints/airings of Three Delivery, early episodes of Random! Cartoons, non-US prints/airings of some episodes of Kappa Mikey, 2007 episodes of SpongeBob SquarePants, and the final season of ChalkZone. It appears without copyright information on non-US prints of Nicktoons Network originals such as Kappa Mikey and Ricky Sprocket: Showbiz Boy (plastering the Nicktoons Originals logo that originally appeared at the end (a print Nickelodeon logo would even replace the print Nicktoons Network logo as well)). The main logo still appears on new episodes of shows that debuted prior to 2007, such as SpongeBob SquarePants, until the episode "Blackened Sponge/Mermaid Man vs. SpongeBob". The Avatar: The Last Airbender variant is preserved on Netflix prints.
 * The version without the copyright info was seen on Charlotte's Web 2 - Wilbur's Great Adventure and the teaser trailer for The Rugrats Movie. It is also retained on Amazon Instant Video prints of SpongeBob SquarePants.
 * From 2001 to 2006, this logo was seen on certain Nicktoons after split-screen credits on Nickelodeon, replacing the 2000 Nickelodeon Productions "Weird Object" logo. This includes Jimmy Neutron, Oh Yeah! Cartoons, The Fairly OddParents (which alternated with "The Weird Object"), ChalkZone, My Life as a Teenage Robot, Danny Phantom, and Invader Zim, which kept their respective logos while all of the other Nicktoons used the regular Nickelodeon Productions logo.
 * Along with "The Weird Object", this can only be found on VHS recordings or encodes online. Also seen on the 1997 SpongeBob SquarePants pilot and the 1998 Jimmy Neutron pilot.
 * The last cartoon to premiere with this logo was El Tigre: The Adventures of Manny Rivera, and the last episode to use it was on the SpongeBob SquarePants episode "Goo Goo Gas/Le Big Switch" (though this episode had aired in other regions almost two years beforehand). It could also be seen on the three super-deformed shorts of Avatar: The Last Airbender, which are preserved on the season 2 DVD release.