Agelasta

In Greek mythology, Agelasta (Ἀγέλαστος in Ancient Greek or Αγέλαστη Modern Greek "smile-less") was the name of the stone on which Demeter rested during her search for Persephone.

In modern culture, Agelasta inspired the title of a documentary by Philippos Koutsaftis (Φίλιππος Κουτσαφτής), called [http://www.imdb.com/title/tt0268898/ Agelastos Petra] - Αγέλαστος Πέτρα "smile-less stone" (2000) on Modern Eleusis.