When Hippodike and the other Danaids who had murdered their husbands they were sent to Tartarus and were forced to carry water from the river Styx in a bowls (or jars according to some) with holes over to a tub which leaks at multiple parts. Erato and the others were told only when they filled the tub could they wash away their sins. The Danaids continue this essentially impossible task to this very day.
Danaus & Herse
Spouse & Lovers
"The youngest sons of Egyptus were these: Idas got Hippodice; Daiphron got Adiante (the mother who bore these damsels was Herse)..."
- Pseudo-Apollodorus, Bibliotheke, 2.1.5