Homer's fugitive mother, Mona Simpson, was for years thought to be dead - by both fans and Homer himself. Voiced by four different actresses through the years (most notably Glenn Close), Mona Simpson actually turned out to be on the run from the law, due to her involvement in various environmental and political movements. Prior to Season 7, Mona had been seen only in flashbacks. Returning to Homer's life in that season's Mother Simpson, Mona became a recurring character in three major episodes as she came and went from Homer's life, much to his annoyance. However, her eventual death in Mona Leaves-a would devastate him, and motivate him to carry out her final wishes - unwittingly sabotaging a missile launch. Coming in the later seasons of the show, Mona's death might have been missed by some fans, so for many, she'll simply always be Homer's hippie outlaw mom, forever on the lam.