Three men are fishing. One catches a magic fish that will grant each one a wish if they let him go.
The first one wishes he could double his IQ. It is done.
The second one wishes to triple his IQ. It is done.
The last one (who is an idiot) wishes to multiply his IQ by a 1/2. The fish asks if he is sure; the man nods.
When the fish grants his wish, he turns into a blond.