This is my giant theory. This spans shows from the 90's, Disney Channel, Disney XD, Nickelodeon, and Netflix. Here it goes.

Perfect Strangers(1986) produces a spin-off, Family Matters(1989), which introduces the character of Steve Urkel. Steve Urkel makes a cameo appearance in the Full House (1987)episode "Stephanie Gets Framed" as a cousin of D.J.'s friend Julie. Steve Urkel appears in the Step By Step(1991) episodes "The Dance" and "A Star Is Born" Dana from Step By Step appears in the Boy Meets World(1993) episode "The Happiest Show On Earth". And also Jesse Katsopolis, Michelle Tanner, Denise Frazier, and Aaron Bailey appeared in the Hangin' With Mr. Cooper(1992) episode "Hangin With Michelle". Sabrina The Teenage Witch(1996) did an event episode where her cat, Salem, ate her crystal ball and turned the shows Boy Meets World, Meego(1997), Teen Angel(1997), and You Wish(1997) into different time periods. As you probably know, Boy Meets World produced a spin-off on Disney Channel called Girl Meets World(2014). Disney Channel held a big crossover event in 2015 called the Monstober Spooktacular Weekend. It had characters from the shows Girl Meets World, Jessie(2011), Austin And Ally(2011), I Didn't Do It (2014), K.C. Undercover(2015), Best Friends Whenever(2015), and Liv And Maddie(2013) crossover into each other. The main cast of Jessie made guest appearances on an episode of the animated series Ultimate Spider-Man(2012). Ultimate Spider-Man has done multiple crossovers with Avengers Assemble(2013) and Hulk And The Agents Of S.M.A.S.H.(2013). Ultimate Spider-Man and Avengers Assemble did a crossover with Phineas and Ferb(2007) titled "Phineas and Ferb: Mission Marvel". Phineas and Ferb also did a crossover with Milo Murphy's Law(2016). But going back to Jessie, it did a two-part crossover with Good Luck Charlie(2010), which in turn did a crossover with Shake It Up(2010). In an episode of Jessie, Mr. Moseby from The Suite Life Of Zack And Cody(2005), makes a cameo appearance. The Suite Life Of Zack And Cody did a crossover event with the shows That's So Raven(2003) and Hannah Montana(2006) called "That's So Suite Life Of Hannah Montana". The Suite Life Of Zack And Cody produced a spin-off show called The Suite Life On Deck(2008). The character Mr. Hashimoto from The Suite Life On Deck appears in an episode of A.N.T. Farm(2011). The Suite Life On Deck did a crossover with Hannah Montana and Wizards Of Waverly Place(2007) called "Wizards On Deck With Hannah Montana". The band from I'm In the Band(2009) also appears in an episode of The Suite Life On Deck. That's So Raven has two spin-offs, Cory In The House(2007), and Raven's Home(2017). Raven's Home is going to do a crossover with Bunk'd(2015), which is a spin-off of Jessie. Full House has a spin-off called Fuller House(2016). In an episode of Fuller House, Stephanie reads a book about Ariana Grande, and talks about the show Sam And Cat. Sam And Cat is a spin-off of iCarly and Victorious. iCarly is mentioned in the Nickelodeon show Game Shakers(2015), which crosses over with Henry Danger(2014), which crosses over with Knight Squad(2018). Henry Danger also crosses over with The Thundermans(2013), which crosses over with The Haunted Hathaways(2013). A character from The Thundermans, Dr. Colosso, appears in an episode of Nicky, Ricky, Dicky, And Dawn(2014).

There are plenty more shows that are in this universe, but I think this is good for now.

Anyone notice how many crossovers and references our favorite shows have to other shows. I've come up with a theory interconnecting all of these shows based on their crossovers. I'll post it soon, as it takes a long time to organize, but it starts with Perfect Strangers and Full House and currently ends with Raven's Home and Bunk'd.

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