10 Genius In-Jokes In The Simpsons
6. Seymour's Cameo
Much as many might not believe it, there are a lot of Simpsons fans who've never watched Futurama, save for the crossover episode "Simpsorama" which occurred during The Simpsons' 26th season.
And while the episode as a whole is a fairly broad cross-pollination of Matt Groening's two most beloved animated shows, there is one killer gag which left Futurama fans heartbroken and everyone else none-the-wiser.
At one point in the episode, we see Homer Simpson, Bender, Fry, and Leela crossing the street by Panucci's Pizza - a Futurama staple that's somehow now in Springfield - and for a second we focus on a small dog briefly waking up and falling back asleep.
Those who don't watch Futurama will be absolutely oblivious, but even the most casual fan won't ever forget that dog.
That dog is Seymour, Fry's pet who in one of the series' most heart-wrenching episodes, "Jurassic Bark," is shown waiting faithfully for a missing Fry to return, ultimately dying of old age before finding out that Fry fell into a Cryotube.
This devastating revelation was admittedly retconned in the Futurama film Bender's Big Score, but to many fans it remains the series' emotional high-point.
Showing Seymour waking up and just barely missing Fry walking past in Simpsorama, then, was like twisting the knife in fans' aching hearts.
As a small bout of solace, the episode is at least accepted to be non-canon by many.