It's the end of an era at Dunder Mifflin. Steve Carell's final episode in The Office aired Thursday night, featuring his fond farewell to the employees of the Scranton paper factory. Carell has played Michael Scott for seven sessions, but is leaving to focus on films. It has yet to be announced who will replace him. Currently, Will Ferrell is playing his interim successor in a four-episode story arc, but speculation abounds as to who the permanent replacement will be. A long list of future guest stars, including Jim Carrey, James Spader, Will Arnett, Ray Romano, and Ricky Gervais, has fueled speculation as to who the new boss will be.