a parable of frogs and scorpions

A scorpion standing by the water asked the frog to carry him across the river.

Then the frog asked.

"How can I believe you don't sting me?"

said the scorpion.

"If I poke you, I'll drown too. Why would I do that?"

The frog began to cross the river with the scorpion on its back, judging that the scorpion was right. However, in the middle of the river, the scorpion placed a poisonous sting on the frog's back.

As they both sank into the water, the frog asked, breathing heavily.

"Why did you stab me? You're going to die, too."

Scorpions also said, breathing heavily.

​
"That's my instinct."