There was once a Buddhist monk who had adopted a poisonous snake, keeping the snake in a cage like a pet.
The Buddha warned this monk that the snake couldn't be trusted, but the monk did not listen.
“I can't live without my snake friend,” he said.
One day the monk went to feed his snake. “Come here, my dear snake,” he said as he opened the cage. "I have food for you!"
Hunger had made the snake impatient, and it bit the monk on the hand.
Thus the foolish monk died, and the snake slithered away into the forest.
Inspired by: The Jataka, translated by Robert Chalmers.
Notes: This is the Veluka Jataka.