Crossover Nexus

Crossover Nexus is a crossover episode of the second season of OK K.O.! Let's Be Heroes.

Synopsis
When K.O. finds himself in a mysterious place, he meets other Cartoon Network heroes and they team up to defeat an evil villain known as Strike.

Characters

 * K.O.
 * Mr. Gar (mentioned)
 * Garnet (Steven Universe)
 * Steven Universe (Steven Universe) (imagined, gemstone in the original 22 minute version)
 * Pearl (Steven Universe) (imagined)
 * Amethyst (Steven Universe) (imagined)
 * Ben Tennyson (Ben 10)
 * Gwen Tennyson (Ben 10) (mentioned, head in the original 22 minute version)
 * Grandpa Max (mentioned)
 * Raven (Teen Titans Go!)
 * Robin (Teen Titans Go!) (shadow cameo)
 * Cyborg (Teen Titans Go!) (shadow cameo, body in the original 22 minute version)
 * Starfire (Teen Titans Go!) (shadow cameo)
 * Beast Boy (Teen Titans Go!) (mentioned, shadow cameo)
 * Strike

Cartoon Network Heroes cameos

 * Moxy (The Moxy Show) (stone, Ben 10's transformation, reanimated)
 * Dexter (Dexter's Laboratory) (Ben 10's transformation)
 * Monkey (Dexter's Laboratory) (stone, Ben 10's transformation)
 * Johnny Bravo (Johnny Bravo) (Ben 10's transformation)
 * Carl (Johnny Bravo) (stone)
 * Cow (as SuperCow) (Cow and Chicken) (Ben 10's transformation)
 * Chicken (Cow and Chicken) (stone)
 * Weasel (I.M. Weasel) (stone, reanimated)
 * Buttercup (The PowerPuff Girls) (Ben 10's transformation)
 * Talking Dog (The PowerPuff Girls) (stone)
 * Edd/Double D (Ed, Edd n Eddy) (stone, Ben 10's transformation)
 * Lu (Mike, Lu, and Og) (stone)
 * Courage (Courage the Cowardly Dog) (stone)
 * Sheep (Sheep in the Big City) (stone)
 * Larry 3000 (Time Squad) (stone)
 * Robot Jones (Whatever Happened to… Robot Jones?) (stone, Ben 10's transformation, reanimated)
 * Abigail "Abby" Lincoln/Numbuh 5 (Codename: Kids Next Door) (stone)
 * Grim (The Grim Adventures of Billy and Mandy) (stone, Ben 10's transformation)
 * Major Dr. Ghastly (Evil Con Carne) (stone)
 * Erin (Miguzi) (stone)
 * Periwinkle (Periwinkle Around the World) (stone)
 * Kiva Andru (Megas XLR) (stone)
 * Frankie (Foster's Home for Imaginary Friends) (stone)
 * Yumi (Hi Hi Puffy Ami Yumi) (stone, reanimated)
 * Juniper Lee (The Life and Times of Juniper Lee) (stone)
 * Lazlo (Camp Lazlo) (stone)
 * Periwinkle (Sunday Pants) (stone)
 * Jake Spidermonkey (My Gym Partner's a Monkey) (stone)
 * Rodney J. Squirrel (SquirrelBoy) (stone)
 * Golly Gopher (Re-Animated and Out of Jimmy's Head) (stone)
 * Chowder (Chowder) (stone, Ben 10's transformation, reanimated)
 * Schnitzel (Chowder) (stone, reanimated)
 * Captain K'nuckles (The Marvelous Misadventures of Flapjack) (stone, Ben 10's transformation)
 * Finn the Human (Adventure Time) (Ben 10's transformation)
 * Jake the Dog (Adventure Time) (watch board, stone, Ben 10's transformation)
 * Generator Rex (Generator Rex) (stone)
 * Mordecai (Regular Show) (Ben 10's transformation)
 * Hi Five Ghost (Regular Show) (stone, reanimated)
 * Ilana (Sym-Bionic Titan) (stone, reanimated)
 * Octus (Sym-Bionic Titan) (stone)
 * Blastus (Robotomy) (stone)
 * Duncan Rosenblatt (FireBreather) (stone)
 * Alfe (The Problem Solverz) (stone)
 * Gumball (The Amazing World of Gumball) (stone, Ben 10's transformation)
 * Festro (Secret Mountain Fort Awesome) (stone, Ben 10's transformation, reanimated)
 * Uncle Grandpa (Uncle Grandpa) (Ben 10's transformation)
 * Jeff Randell (Clarence) (stone, Ben 10's transformation)
 * Jorel's Brother (Jorel's Brother) (stone)
 * Wirt (Over the Garden Wall) (Ben 10's transformation)
 * Gregory (Over the Garden Wall) (stone)
 * Jason Funderburker (Over the Garden Wall) (stone)
 * Grizzly Bear (We Bare Bears) (stone, Ben 10's transformation)
 * King Rufus (Long Live the Royals) (stone)
 * Prohyas Warrior (Mighty Magiswords) (watch board, stone, Ben 10's transformation)
 * Black Hat (Villainous) (stone)
 * Apple (Apple & Onion) (stone)
 * Kelsey (Craig of the Creek) (stone)
 * Mortimer (Craig of the Creek) (stone)
 * Hedeghog (Summer Camp Island) (stone)
 * Valentino (Victor and Valentino) (stone)
 * Mao Mao (Mao Mao: Heroes of Pure Heart) (stone)
 * One-One (Infinity Train) (stone)
 * Tiggy (Tig N' Seek) (stone)
 * Seth (The Fungies) (stone)
 * Pam (The Fungies) (stone)
 * Noods
 * Clyde 49 (graffiti cameo)

Blocks, Eras, Promos, etc.

 * Toonix (Era; Latin American counterpart of Noods; graffiti; 2010-2012)
 * Fridays (programming block, 2003-2007)
 * Tickle U (programming block; 2005-2007)
 * Check it (era; 2010-2016)
 * YEEEAUHHH! (slogan)
 * New New New New (slogan; 2017-2018)
 * Cartoon Planet revival (programming block; 2012-2014; graffiti)
 * Har Har Tharsdays (programming block; 2008-2010)
 * JBVO (programming block, Johnny Bravo spin off; 2000-2001)
 * Cartoon Cartoon (name formerly used for Cartoon Network originals)
 * Shorties (a series of short based on Hanna Barbera cartoons)
 * Yes (era; 2006-2007)
 * Dude!
 * Flicks (programming block)

Trivia

 * The episode is a tribute to Cartoon Network, and the first episode to reference Cartoon Network, and Cartoon Network's 25th Anniversary.
 * This episode is also a love letter to Cartoon Network, for making all the work happen.
 * This is the first time Cartoon Network was referenced in the O.K. K.O.! universe.
 * Originally the episode was supposed to air during Cartoon Network's 25th Anniversary, but moved it to the year 2018.
 * This is the only time K.O. met Garnet, Ben and Raven.
 * The idea of Crossover Nexus came from the Point Prep Arc, a location of OK K.O.! Let's Be Heroes.
 * The crossover was meant to be 22 minutes, but Cartoon Network decided to cut it down to 11 minutes so the crossover could take place in CN City.
 * The crossover was announced during San Diego Comic Con 2018.
 * New theme songs of Cartoon Cartoons, CN City, and Fridays were played.
 * it's the Friday Night song (2003-2007) was a slow depression music and was played during the scene where K.O., Garnet, and Ben are inside the Screwy Ain't It building and discover lots of Cartoon Network heroes that were summoned and defeated by Strike.(Note: it is not heard clearly unless if it was muted and the music plays in the background insted ).
 * The Cartoon Cartoons one was a remixed music and was played during the scene where Ben transforms into multiple Cartoon Network characters to defeat Strike.
 * The CN City one was an opera music and was used during the scene where CN City is being restored by Strike's pen.
 * The crossover officially marks the very first (and currently only) time that Moxy (from The Moxy Show) was featured in an official Cartoon Network product since Cartoon Network's 10 years in 60 seconds tribute video in 2002.
 * Periwinkle (from the lost Cartoon Network anthology series, Sunday Pants) made a cameo in this episode, which also marks the first and currently only time that Sunday Pants was featured in official Cartoon Network media.
 * Two characters came from Two Cartoon Network originals that weren't created in the US: Jorel's Brother (from Jorel's Brother) and Black Hat (Villainous).
 * Jorel's brother's cameo was most likely due to Ian Jones Quartey's visit to Brazil in 2017, where he was at a Comic Con experience to do a live drawing with Juliano Enrico, the creator of Jorel's Brother.
 * Black Hat with the heroes was very strange because he is a villain even though he's the protagonist of Villainous. However, according to an episode of "Videos of Guidance for villains: Q & A Blackhat Organization responds", stone Black Hat was actually a clone from the short, The Perception of Evil.
 * The Cartoon Network originals that didn't appeared in the crossover were:
 * Scooby-Doo ( due to the series being owned by Warner Bros. )
 * Looney Tunes ( due to the series being owned by Warner Bros. )
 * Yogi Bear ( due to the series being owned by Warner Bros. )
 * Tom & Jerry ( due to the series being owned by Warner Bros. )
 * Pokemon ( due to the series being owned by Nintendo. )
 * Sonic Boom ( due to the series being owned by Sega. )
 * Class of 3000
 * The Secret Saturdays
 * What A Cartoon!
 * Peppa Pig ( due to the series being owned by nick jr )
 * Space Ghost: Coast to Coast (due to the series being from Adult Swim since 2001)
 * Mixels (as it was co-produced by LEGO)
 * Star Wars: Clone Wars (due to Disney being the current owner of the Star Wars franchise)
 * Transformers Animated (due to Hasbro owning all Transformers media)
 * Total Drama ( due to the series being from Teletoon )
 * Total Dramarama ( due to the series being from Teletoon )
 * Johnny Test
 * Ben 10 (original series), Ben 10: Alien Force, Ben 10: Ultimate Alien, and Ben 10: Omniverse.
 * Big Bag
 * Live action shows: Dude, What Would Happen, Destroy Build Destroy, etc.
 * blocks, promos, and other stuff that didn't appeared in Crossover Nexus were:
 * Cartoon Network's Cartoon Theatre (programming block)
 * You are Here (programming block)
 * The Cartoon Cartoon Top 5 (programming block)
 * Are You CN what we're Sayin'? (slogan)
 * Wedgies (series of Cartoon Network pilots)
 * The Cartoon Cartoon Show (programming Block)
 * Cartoon Network Invaded (crossover TV event; 2007)
 * Fall (era; 2007-2008)
 * there are poster of shows on the wall witch includes:
 * Dexter's Laboratory
 * The Powerpuff Girls
 * Yogi Bear
 * Adventure Time
 * Samurai Jack
 * Steven Universe
 * Johnny Bravo
 * Regular Show
 * We Bare Bears
 * Ed Edd n Eddy
 * Craig Of The Creak
 * The Amazing World of gGumball The Grim Adventures Of Billy & Mandy
 * Ben 10

Model Sheets
According to Ian Jones-Quartey, the crossover characters used their official models from their home shows with the exception of Moxy and the Noods due to not being 2D form.