A friend recently told a sad story:

I’ve been such a fucker since I was a kid. In the kindergarten, the teacher told us a story about a little girl who entered one ear of a cow and came out of the other (a little cowboy). So, I was a curious guy, not long thinking of the scale, stuck the pencil of his neighbor on the stool in the ear, hoping that he will come out of the other... but the blood went out.
Morality: it is inappropriate to tell children such dumb tales, children can be too curious