Homer's Evolution is the twelth couch gag of Season 18 and the second longest couch gag ever used on the show (The first being the Rick and Morty Couch Gag from "Mathlete's Feat"). It starts with Homer as a single-celled organism and going through time to become the modern day Homer.
A single-celled organism, resembling Homer, separates into a lot of cells (all of them yelling "D'oh!") and eventually turns into a jellyfish and then into a fish-like creature and swims onto land, avoiding an octopus Mr. Burns who tries to catch him. It grows legs and turns into an amphibian that eats a dragonfly-like Lenny. He walks along and keeps evolving from a dimetrodon to a primitive mammal as he sees dinosaurs and a pteranodon resembling Agnes Skinner; a tyrannosaurus rex resembling Bart tries to eat him, and a stegosaurus resembling Lisa prevents Bart from eating Homer by swiping at him with her tail. After surviving the meteor that wiped out the dinosaurs, Homer continues jumping from tree to tree to become an ape. He becomes a caveman walking in a snow storm, while another caveman Moe, devolves into a small, shrew-like animal as he walks the other way. Caveman Homer then evolves into a Arthurian villager, a conquistador, then a pilgrim, then a Victorian Era gentleman, and eventually becomes the modern Homer. He gets to his house and sits on the couch, when Marge asks him what took him so long. Homer then sighs in exhaustion.
Behind the Laughter
There are two versions of this couch gag that aren't different until the end. The first and original version is used in "Homerazzi", where Marge asks Homer what took him so long, with Homer sighing. The second version is used in "The Homer of Seville" and "Mona Leaves-a", where she asks him "Did you bring the milk?" (however the closed captionings still says "What took you so long?" in the second version).
- Homer Simpson
- Marge Simpson
- Santa's Little Helper (sleeping)
- Bart Simpson (also as a Tyrannosaurus)
- Lisa Simpson (also as a Stegosaurus)
- Maggie Simpson
- Moe Szyslak (devolving from a caveman to a rat)
- Agnes Skinner (as a pteranodon)
- Mr. Burns (as an octopus)
- Lenny (as a dragonfly)
- Single-Celled Organism (Homer)
- Jellyfish (Homer)
- Primitive Cephalopod (Mr. Burns)
- Haikouichthys (Homer)
- Amphibian-like Fish (Homer)
- Proterogyrinus (Homer)
- Dimetrodon (Homer)
- Meganeura (Lenny)
- Pteranodon (Agnes Skinner)
- Tyrannosaurus Rex (Bart)
- Stegosaurus (Lisa)
- Purgatorius (Homer and Moe)
- Bigger mammal (Homer)
- Apidium (Homer and Moe)
- Australopithecus (Homer and Moe)
- Cro-Magnon (Homer and Moe)
- Episode – "Homerazzi"
- Episode – "The Homer of Seville"
- Episode – "Mona Leaves-a"
- Episode – "At Long Last Leave" (Snapshot montage with other episode's gags)