In a whole bunch of myths, Zeus is the one doing bad stuff. Like the many corrupt politicians to follow, Zeus spends about half his time seducing innocent young maidens and the other half trying unsuccessfully to hide his affairs from his fuming wife Hera. In the story Sisyphus, however, Zeus takes on his role as the supreme judge of the universe.
When there's some imbalance (like a soul escaping the Underworld) it's Zeus's job to make sure things are put back to rights. Though Thanatos fails him at first, Zeus eventually sends Hermes to make sure that Sisyphus is trapped in the Land of the Dead for good and suffers appropriately for all eternity. (Maybe Zeus should get one of those Judge Judy kind of shows. Judge Zeusy sounds good to us.)