A decisive point in an argument when somebody's point becomes entirely invalid by making a simple mistake. Derived from the thought process of stepping on a Green Bean while delivering a skull crushing comeback.
Person 1: "so to conclude, I **stutters** I.."
Person 2: "nah shut up man thats a green bean moment, you're done"
When your mom walks into your room while your jacking off, and she says, “The cucumbers are ready!” She drops them on her toes/feet while you nut in her face.