6. George Carlin (1937-2008)
One of the most popular stand-up comics of his era, George Carlin only ever made his way to Springfield once; in "D'oh-in In The Wind," Carlin voiced "Munchie," a hippie/yuppie alongside Martin Mull's "Seth." Munchie and Seth played a huge part in this episode, as they helped Homer learn his middle name ("
From now on, I'm Homer JAY Simpson!") and assisted Homer in a fun "freaking out the squares" segment. Unfortunately, Munchie and Seth's fates are open to interpretation, as Chief Wiggum was apparently set to arrest them due to Homer's inadvertent drugging of the entire town (using the hippies' "secret stash" to make their Garden Blast juice drink) before Homer is shot in the head with a flower. If Munchie did avoid prison, and had Carlin not passed away of heart failure in 2008, both Munchie and Seth could have returned numerous times, including 2008's "Mona Leaves-a" (the death and funeral of fellow hippy Mona Simpson) and as part of the flashbacks in 2012's "How I Wet Your Mother," the last (to date) appearance of Mona, or at any number of protests of Mr. Burns and the Nuclear Power Plants' wrongdoings.