Teaching can be an incredibly rewarding job, but it can also be incredibly draining. Corralling a classroom full of rambunctious children and attempting to keep a peace while inspiring learning is no small task, and some teachers have to get extra creative to keep kids on their toes.
While obviously honesty is the best policy, there are times when teachers (much like parents) twist the truth a bit to get children to do what they need. Sometimes these little white lies are completely fantastical, and easily disproven when children become old enough to know how the world works. Other times, however, they hit closer to reality and leave adults looking back wondering exactly what their teacher was hiding.
Not a teacher, but a camp counselor. I helped lead archery instruction sometimes, and I have a little round scar, smaller than a dime, on my torso. When I told them about range safety (shooting only when told, not pointing your bow at others, and not shooting when there's someone on the range), I showed them my scar and said that I got shot once last year when I was collecting arrows and someone shot down the range anyway.