There's this town with two blacksmiths - one, a swordsmaker and the other, a shield maker. The swordsmaker's swords can slice through anything as a rule and the other guy's shields cannot be destroyed. Now they get cut up with each other for some reason and pit their wares against each other. What do you expect happens?
(In reply to
Ideal answer by Alan)
Short of "What happens when an irresistable force meets an immovable object? *An inconceivable event*", I think Alan's response is probably the best.