Rusty Spoon Effect

This is when a person does something so bloody unexpected, so stupid, that it actually works.
Just like a terrorist running at you with not a bomb, but a rusty spoon

E.g. You go round a corner expecting someone to jump you, but they are actually lying down in the middle of the hallway

Person 1 - "Scared you!"
Person 2 - "You where duct taped to the ceiling, bloody Rusty Spoon Effect"