A scorpion once met a frog on the bank of a stream.
“Could you please carry me across this stream on your back?” the scorpion asked.
The frog was reluctant.
“How do I know you won’t sting me?” the frog said.
“Because if I sting you, you’d die, and I’d die too.”
Satisfied with the scorpion’s answer, the frog agreed. The scorpion crawled up on the frog’s back, and they set out.
Halfway across the stream, the scorpion stung the frog in the back. The frog began to sink. As expected, they were both going to drown.
The frog gasped just before going under, asking one final question. “Why?”
“It’s my nature,” said the scorpion.