Here's a little info I got on a Google search talking about Taz and the Duster, from however when they introduced the Duster,
http://www.groupsrv.com/hobby/about378959.html :
" ..... however when they introduced the Duster, they wanted to
use the Tazmanian devil aka Taz for the "Duster swirl". Here a quote from a
old article of Collectible Automobile of April 1999 issue about the 1970-76
Plymouth Duster,".....they wanted to use it directly but couldn't get the
rights from Warner Bros. They wanted maybe 10 times as much money (as they
charged to use the Road Runner name) because the Road Runner name had
undervalued by Warner. So we did our own devil..."