We get a double whammy in this episode: both the arrival of an alien species and the extinction of a domestic one. Sunrise sunset, ashes to ashes, mud to mud. It would be a poetic depiction of Mother Nature's annoyingly cyclical patterns, if the two weren't directly related to each other. Turns out, the crustacean-like decapodians love to scarf anchovies so much that they fished the entire population right off the globe and down their gullets. A shame for any degenerate human who likes weird oily fish on their pizza.
Of all the wacky aliens depicted in Futurama, why is this the only time in the show's entire run that we learn of their meeting with humanity? Were decapodians first contact? Did we cower in horror behind our television sets as our president strode out to meet the creepy crab people, only for them to order a large pizza with knockoff sardines? Or did we just file their arrival away with all the other aliens that had been bunking on our planet for decades? If that was the case, who was the first? Niblonians? Cygnoids? Whatever Morbo is?
If I were the conspiricy theory type (which I am, beacause that's what the ghost of J. Edgar Hoover hired me to be), I'd say that there's a reason decapodians were singled out, specifically in relation to anchovies. You see, there's this concept in biology known as carcinisation, in which animals just can't help themselves from evolving into crabs. No really, it turns out that the crustacean world is so jealous of the superior life-form that is the crab that they're all falling over themselves, in humorous slow motion, to become them. Being a crab is the shellfish version of being a youtuber, everyone wants in but doesn't realize that there's only so much room in the ocean marketplace and you're probably way more awkward on camera than you think. Yeah, it primarily effects crustaceans, but in a couple hundred years who's to say the concept won't make the short hop to other ocean-dwelling creatures, like fish? Like anchovies? Are decapodians even real, Matt?
Give it a few centuries and we'll all be ordering weird oily crabcake pizza with butter sauce, I guarantee it. I'm also hungry now.