When he came upon an impassable river.
A fox came to the riverbank bank and, before he could pass, the scorpion asked if he would take him across with him.
"No," replied the fox. "Because you'll sting me and I'll drown."
"I wouldn't do that," said the scorpion. "We'd both drown."
The fox contemplated it for a few moments before agreeing.
The scorpion climbed up on the fox's back and the two set off across the river.
They were only half-way across when the scorpion stung the fox.
Paralyzed and sinking below the water, the fox asked: "Why did you do that? Now we'll both drown."
"I couldn't help it," said the scorpion. "It's in my nature."
Goddamn parables, man.