Joe,
although I am insulted that I did not get a link to this thread ;-) :

Badewannen-Entchen is not used in German. More popular is Gummiente (with or without hyphen) or Gummientchen.
If the Gummiente is able to make squeaking sounds, it might also be called Quietsch-Entchen (with or without hyphen), or Quietsche-Entchen.
MudGuard