Shortly after Stephen Hillenburg's death (RIP), I began thinking about how he was only unfortunately able to make one cartoon series in his lifetime.
I find this odd because almost every successful cartoon creator gets a chance to make at least two shows in their lifetime. Matt Groening had The Simpsons, Futurama, and Disenchantment, Joe Murray had Rocko's Modern Life and Camp Lazlo, Genndy Tartakovsky had Dexter's Lab and Samurai Jack, Craig McCracken had The Powerpuff Girls, Foster's Home for Imaginary Friends, and Wander Over Yonder, the list goes on.
So, let's say ITTL, shortly after stepping down as the SpongeBob SquarePants showrunner in 2004, Hillenburg makes a new show, either on Nickelodeon, Cartoon Network, or even Disney Channel. This show runs until sometime before Hillenburg returns to SpongeBob in 2015.
Now the question is: what would this other show be about? I know Hillenburg was a marine biologist, but if it was ocean-themed like SpongeBob, it would probably end up being too similar. In fact, unless it had a completely different tone, it would probably have difficulty living up to the high bar SpongeBob set. While I'm unsure of whether this new show would be well-liked or not, that doesn't mean it couldn't be successful. (See Johnny Test and Teen Titans Go.)
Also, what other effects would this show have ITTL? Which existing show(s) would have to be butterflied away?