The Most Memorable Grey's Anatomy Guest Stars

Sarah Paulson
Episode: "The Time Warp"

For years, we'd heard about the legendary Ellis Grey, who won the Harper Avery twice and created the laprascopic Grey method, but it wasn't until Paulson takes on the role in the 1982-set flashback episode "The Time Warp" do we get to see Meredith's mother in all her glory as she and Richard, outcasts for their gender and race, respectively, diagnose a patient with GRID (a precursor to AIDS).