The Bodhisatta was once a rat. He lived in the forest and was the leader of a big group of rats. A jackal came up with a scheme to eat the rats by staying near their cave and pretending to be holy. When the Bodhisatta saw the jackal he asked his name and why he stood on one leg facing the sun while loudly inhaling air. The jackal answered that his name was Godly and if he stood on all four legs the earth could not bear his weight, he faced the sun to worship it, and air was his only food.
The Bodhisatta fell for the con and began to take all the rats to pay respect to the jackal every morning and evening. And each time the rats left, the jackal lunged down to eat the last one and lick his lips clean before any others could see what had happened. Eventually the rats noticed their group had grown smaller and they told the Bodhisatta. Hearing this news, he suspected it was the jackal, so the next time they went to worship, he walked at the end of the line. When the jackal began to strike, the Bodhisatta turned around to rebuke him and then sprang at the jackal’s throat, biting hard into his windpipe and killing him. The other rats came back and devoured the entire body.
In the Lifetime of the Buddha
The jackal was an earlier birth of one of the Buddha’s disciples who had been exposed as a hypocrite. The Buddha told this story so the other disciples knew he had been the same way in the past.