Why Did Charlie Adler (AKA Starscream) Quit "Tiny Toons Adventures"? Why did Silverbolt quit Tiny Toons? Let's find out. Here's Some History. Buster was the last and hardest voice role to cast. Buster's original voice actor was Charlie Adler, of whom producer Tom Ruegger said, "Sometimes he went too gravelly and over the top, but brought a great deal of energy to the role". Executive producer Steven Spielberg and other producers objected to Adler, but Ruegger and casting director Andrea Romano recommended him. When Adler was chosen for the role he said in an interview, "This is the first time in 30 series I have been in [as a voice actor], that I'm having the best time of my life working". During the third season, when they started production on Animaniacs, Adler was disappointed that he did not get a recurring character in the new show, while minor Tiny Toons actors like Rob Paulsen and Frank Welker were given main roles. Adler sent angry letters to Ruegger and other producers, citing that his treatment had been "shabby" and that he was going to leave the show. When Adler dropped out, the studio still had a handful of episodes to record, so they re-cast the role of Buster with John Kassir. Kassir's voice was slightly different than Adler's: Adler's voice had been more gravelly and rough, whereas Kassir's was smoother. Kassir finished the last 10% of Adler's lines from "The Horror of Slumber Party Mountain". He performed Buster's voice in "The Return of Batduck" and "It's A Wonderful Tiny Toons Christmas Special" in 1992; in 1994 and 1995 he reprised the role for "Night Ghoulery", and "Tiny Toons Spring Break Special". For the promos on Kids WB, Buster was played by various other voice actors, such as Billy West. PS: Both Adler and Welker are the only 2 Tiny Toons Actors in the Transformers Movies.