Where a character gets stabbed or shot - usually in the kidney - and it should be fatal. Only it isn't, because they donated that kidney. Or they have dextrocardia. Or that limb was actually prosthetic. Usually given as justification for Only a Flesh Wound, but sometimes the central conceit around which a climax - or entire plot - is built. Usually used as an ironic counterpoint to the original injury. This is all but guaranteed to happen to people cheated out of organs earlier in the plot, because it's a good way of suggesting ambiguity - after all, if they still had that kidney they were tricked into donating, they'd be dead now.