Two guys walk into a bar. The third one should have seen it coming.

This joke takes a delightful detour from the usual "walks into a bar" setup, twisting our expectations with a clever bit of wordplay and absurdity. The initial line, "The third one should have seen it coming," plays directly into the common understanding of someone physically bumping into something. We picture a literal, solid bar, perhaps a low beam or a counter. The humor builds on this established trope, leading us to anticipate a clumsy mishap.

However, the punchline cleverly flips the script. By revealing it was an "invisible bar," the joke injects a dose of surrealism and unexpected irony. The initial assumption of a visible obstacle is shattered, making the "should have seen it coming" line hilariously impossible. It's the unexpected twist that makes us chuckle, as the seemingly simple setup morphs into something far more imaginative and silly than a mere stumble. This kind of humor thrives on subverting common phrases and expectations, turning a familiar setup into a surprising and illogical scenario.