So "chase" cartoons were a pretty big thing back in the day, but they were all really repetitive. Cat versus mouse. Mouse wins because cats are stupid. Same old same old.
So WB are brainstorming about a way to deconstruct this model, and try to pick out the STUPIDIST pair of animals to chase one another.
"A pangolin and a crocodile!"
"A raccoon and a walrus!"
"A roadrunner and a coyote!"
So, as they were writing, they decided to change the dynamic. Instead of cat versus mouse, or rabbit versus hunter, they took a different route...
Example. Coyote is at the edge of a cliff where the road just runs off into the abyss. He sees Roadrunner come zooming down in the distance, and hatches a plan.
He quickly and cartoonly paints a big fake picture of the road continuing onwards and places it at the edge of the cliff. He expects RR to come flying in, run into the paper, and fall to his death.
However, when RR comes along, he runs into the painting, and disappears into the horizon.
Coyote looks into the camera, smiles, and chases RR into the painting too.... But falls through and plummets to the ground.
He picks himself up, looks into the camera, and just shrugs, as if to say, "what else did I expect?'
You see, you can't empathise with a mouse outwitting a stupid cat, or a wise-cracking rabbit dancing intellectual circles around a moron, but we all feel for the coyote. His is not a story of coyote versus roadrunner, but if coyote versus the universe. No matter how hard he tries, the world just changes it's laws to turn things against him. He goes to drop a rock off a cliff to land on the RR, but as he anticipates the crash, nothing happens. There's silence... until the boulder comes falling down from the sky and crushes him.
And that's something we can all relate to.