premise: Buffy the Vampire Slayer is created by Joss Whedon.
hypothesis: Buffy the Vampire Slayer is an American television series created by Joss Whedon under his production tag , Mutant Enemy Productions with later co-executive producers being Jane Espenson , David Fury , David Greenwalt , Doug Petrie , Marti Noxon , and David Solomon . Drusilla , or Dru , is a fictional character created by Joss Whedon and David Greenwalt for the American television series , Buffy the Vampire Slayer and Angel .