Watermelons

There was a farmer who grew watermelons. He was doing pretty well, but he was disturbed by some local kids who would sneak into his watermelon patch at night and eat his watermelons.

After some careful thought, he came up with a clever idea that he thought would scare the kids away for sure.
He made up a sign and posted it in the field. The next night, the kids showed up and they saw the sign